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TREASURY  DEPARTMENT 

UNITED  STATES  COAST  GUARD 


HANDBOOK 

ON 

CARE  AND  OPERATION  OF 
GASOLINE  ENGINES 


PREPARED  UNDER  DIRECTION  OF 
THE  CAPTAIN  COMMANDANT 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 
1917 


ADDITIONAL  COPIES 

OF  THIS  PUBLICATION  MAY  BE  PROCURED  FROM 

THE  SUPERINTENDENT  OF  DOCUMENTS 

GOVERNMENT  PRINTING  OFFICE 

WASHINGTON,  D.  C. 

AT 

10  CENTS  PER  COPY 


LETTER  OF  PROMULGATION. 


TREASURY  DEPARTMENT, 
UNITED  STATES  COAST  GUARD, 

Washington,  January  IS,  1911. 

The  following  "  Handbook  on  Care  and  Operation  of  Gasoline 
Engines  "  has  been  prepared  by  Second  Lieutenant  of  Engineers 
W.  M.  Prall,  United  States  Coast  Guard,  and  is  issued  to  officers 
and  enlisted  men  of  the  Coast  Guard  for  the  information  and 
guidance  of  all  concerned. 

E.  P.  BEBTHOLF, 
Captain  Commandant. 
3 


357468 


HANDBOOK   ON   CARE   AND   OPERATION  OF 
GASOLINE  ENGINES. 


CHAPTER  I. 


PURPOSE  FOB  WHICH  THIS  PAMPHLET  IS  ISSUED. 

No  attempt  has  been  made  in  the  preparation  of  this  pam- 
phlet to  cover  all  the  phases  of  design,  construction,  and  opera- 
tion of  gasoline  engines.  It  is  not  expected  that  the  contents 
will  be  of  any  material  aid  to  the  person  who  has  had  consid- 
erable experience  in  handling  these  engines.  The  sole  object 
in  view  is  to  present  the  subject  of  gasoline  engines  in  such  a 
manner  that  persons  without  special  education  or  practical 
training  along  mechanical  lines  can  acquire  a  good  general  idea 
of  how  these  engines  work,  how  they  should  be  cared  for,  and 
the  special  meanings  of  words  and  expressions  when  used  in 
connection  with  engines  of  this  type.  In. other  words,  these  few 
chapters  are  intended  as  a  sort  of  primer  for  the  use  of  enlisted 
men  intrusted  with  the  care  and  operation  of  gasoline  engines. 

Manufacturers  .of  gasoline  engines  and  of  gasoline  motor 
vehicles  often  publish  information  and  instructions  concerning 
their  products  for  the  guidance  of  their  patrons.  Frequently, 
however,  these  articles  make  use  of  such  technical  terms  and 
expressions  that  a  reader,  who  has  not  made  a  study  of  the  sub- 
ject, soon  becomes  confused  and  discouraged.  In  some  cases, 
too,  these  articles  are  written  with  the  purpose  of  convincing 
the  reader  that  the  design,  materials,  and  method  of  construc- 
tion of  the  particular  engine  described  are  the  only  ones  that 
can  be  used  with  success. 

5 


6  CAR!   /  JTD  OPERATION  OF  GASOLINE  ENGINES. 

There  is  also  available  at  present  an  abundance  of  literature 
on  the  subject  of  the  gasoline  engine,  which,  though  thoroughly 
reliable,  is  written  for  the  use  of  trained  designers  and  engi- 
neers, but  is  of  little  value  to  others. 

This  pamphlet  is  prepared  with  the  hope  that  it  will  enable 
the  reader  to  gain  sufficient  knowledge  of  the  subject  to  make 
possible  the  reading  of  more  extensive  works  with  understand- 
ing, and  enable  him  to  secure  the  most  satisfactory  service  from 
an  engine  of  which  he  has  charge. 


CHAPTER  II. 


GASOLINE. 

What  gasoline  is. — In  certain  parts  of  the  world  large  tracts 
of  land  have  been  found,  underlying  which  are  immense  quanti- 
ties of  inflammable  liquid  commonly  known  as  crude  oil.  In  this 
country  there  are  three  principal  oil  regions :  The  Pennsylvania, 
which  includes  parts  of  West  Virginia  and  Ohio ;  the  Texas 
region,  which  extends  into  Oklahoma  and  Kansas ;  and  the  Cali- 
fornia region.  To  obtain  the  oil,  wells  are  drilled  to  depths 
varying  from  an  average  of  about  100  feet  in  the  Pennsylvania 
region  to  3,000  or  5,000  feet  in  California.  Occasionally  upon 
drilling  a  well  the  oil  is  forced  violently  to  the  surface  of  the 
earth,  forming  what  is  known  as  a  "  gusher,"  but  more  often 
the  oil  has  to  be  removed  from  the  wells  by  means  of  pumps. 

This  natural  oil  is  usually  thick,  heavy,  and  dark  brown  or 
green  in  color.  But  crude  oil  is  really  a  mixture  of  several  kinds 
of  oil,  differing  greatly  in  their  nature,  and  quite  easily  sepa- 
rated one  from  the  other  by  the  process  known  as  distillation. 

To  better  understand  the  nature  of  crude  oil  let  us  consider  a 
liquid,  fresh  water,  for  example,  which  is  not  a  mixture  of  dif- 
ferent kinds  of  liquids.  When  a  vessel  of  pure  fresh  water  is 
boiled,  a  gas  known  as  steam  is  formed,  which  can  be  carried  to 
a  cooling  chamber  and  condensed ;  that  is,  cooled  until  it  again 
becomes  liquid.  No  matter  how  much  of  the  water  from  the 
vessel  has  boiled  away,  the  condensed  steam  is  always  found  to 
be  water,  the  last  drop  condensed  being  exactly  like  the  first 
drop,  and  all  exactly  like  the  water  which  was  boiled. 

7 


8  CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

When  crude  oil  is  slightly  heated  gases  are  given  off  which 
may  be  condensed  to  a  liquid  by  cooling.  This  liquid  is  not  at 
all  like  the  original  oil,  but  is  quite  colorless,  light  as  compared 
with  crude  oil,  and  easily  vaporized  (changed  to  the  form  of 
gas)  by  slight  heating.  The  crude  oil,  if  further  heated,  con- 
tinues to  give  off  gases  which,  when  condensed,  form  a  liquid 
much  like  that  first  obtained,  but  slightly  heavier  and  not  quite 
so  easily  vaporized.  This  process  can  be  continued  and  a  whole 
series  of  liquids  obtained,  each  slightly  heavier  and  less  easily 
vaporized  than  the  one  before  it,  until  the  product  is  no  longer 
colorless,  but  yellow,  green,  or  brown.  The  first  liquids  thus 
obtained  are  not  of  much  use  commercially.  They  vaporize  so 
rapidly  that  explosive  gas  is  generated  at  ordinary  temper- 
atures, making  these  oils  too  dangerous  for  ordinary  use.  After 
these,  however,  comes  a  series  of  oils  which  are  of  great  value 
in  modern  life,  known  as  gasoline,  kerosene,  and  lubricating 
oils.  Gasoline  is  the  part  of  crude  oil  obtained  after  the  lighter 
liquids  referred  to  above  have  been  distilled  off  and  while  the 
heating  proceeds  from  about  230°  F.  to  about  280°  F. 

Kerosene  is  obtained  as  the  distillation  continues  between 
280°  and  500°.  After  that,  lubricating  oils  are  produced.  The 
remainder,  a  thick,  heavy,  sticky  oil,  is  suitable  for  use  as  fuel, 
and  is  used  in  some  parts  of  the  country  for  firing  locomotives, 
making  steam  for  factories  and  power  plants,  and  as  fuel  on 
steam  vessels. 

It  is  with  gasoline  that  we  are  interested,  this  short  descrip- 
tion of  one  process  of  refining  crude  oil  being  given  to  explain 
what  gasoline  is,  where  it  is  obtained,  and  how  it  may  be  pro- 
duced. Several  methods  are  used  commercially  to  separate  these 
products,  but  all  depend  upon  the  difference  between  the  boiling 
temperature  of  the  various  liquids.  Recently  attempts  which 
promise  to  be  successful  have  been  made  to  perfect  processes  by 
which  the  heavier  oils  can  be  converted  into  more  valuable  lighter 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.  9 

oils.  This  can  be  done,  but  the  commercial  success  of  the  under- 
taking depends  upon  the  cost  of  the  operations  and  the  difference 
between  the  price  obtainable  for  the  oil  before  and  after  treat- 
ment. 

How  gasoline  produces  power. — Chemists  tell  us  that  gasoline 
is  composed  principally  of  carbon  and  hydrogen.  Carbon  we  are 
familiar  with  in  the  form  of  charcoal  and  coke,  which  substances 
fire  practically  pure  carbon.  Hydrogen  is  a  gas.  It  is  due  to 
processes  of  nature,  very  little  understood,  even  by  the  chemists, 
that  these  two  elements  have  been  so  united  that  they  form  oil. 

Air  is  a  mixture  of  two  gases,  oxygen  and  nitrogen;  these 
gases  are  not  united  with  each  other,  but  simply  mixed  together, 
as  pepper  might  be  mixed  with  salt. 

When  gasoline  vapor  is  mixed  with  air  in  the  proper  propor- 
tions we  have  what  is  called  an  explosive  mixture.  As  long  as 
the  mixture  is  kept  cool  no  action  will  take  place,  but  let  the 
least  part  of  the  mixture  be  sufficiently  heated  and  a  change  will 
occur,  so  violent  that  it  is  termed  an  explosion. 

What  happens  to  cause  this  violent  action?  In  the  first  place, 
it  may  be  said  that  the  carbon  and  hydrogen  are  held  together  in 
gasoline  by  an  attraction  that  is  very  weak.  When  mixed  with 
air  and  heated,  the  carbon  and  hydrogen  no  longer  stay  united 
as  gasoline,  but  each  is  strongly  attracted  to  the  oxygen.  The 
carbon  suddenly  unites  with  part  of  the  oxygen  present  and 
forms  a  gas  known  as  carbon  dioxide,  and  the  hydrogen  unites 
even  more  suddenly  with  the  other  part  of  the  oxygen  and  forms 
water.  This  sudden  action  creates  a  large  amount  of  heat, 
which  causes  the  temperature  of  the  carbon  dioxide  and  water 
to  rise  very  high,  so  high  that  the  water  is  present  only  in  the 
gaseous  form  of  steam.,  Nitrogen  present  in  the  mixture  does 
not  change,  though  its  temperature  is  raised  by  the  heat  of  the 
other  gases. 

It  is  well  known  that  a  gas  if  highly  heated  expands  to  sev- 
eral times  its  original  volume,  or,  if  it  is  heated  when  confined 


10         CAEE  AND  OPEBATION  OF  GASOLINE  ENGINES. 

in  a  closed  vessel  so  that  it  can  not  expand,  it  creates  a  high 
pressure.  It  is  because  of  these  facts  that  gasoline  can  be 
used  as  a  source  of  power  in  the  gasoline  engine,  and  it  is 
evident  that  what  is  commonly  regarded  as  the  dangerous  prop- 
erty of  gasoline,  the  explosiveness  of  the  gas  generated  there- 
from, is  also  the  very  property  that  makes  it  so  useful. 

Precautions  that  must  be  taken  in  handling  gasoline. — There 
are  two  chief  sources  of  danger  from  gasoline  if  it  is  not  prop- 
erly handled — the  danger  of  fire  and  the  danger  of  explosion. 
As  gasoline  evaporates  rapidly  in  the  presence  of  air,  it  forms 
a  rich  mixture  of  inflammable  gas  near  the  surface  of  the  liquid. 
If  ignited  this  gas  burns  rapidly ;  the  heat  accelerates  evapora- 
tion from  the  surface  and  causes  the  volume  of  flarne  to  increase 
with  great  rapidity. 

To  avoid  the  danger  of  fire,  gasoline  should  always  be  kept  in 
strong,  tight  tanks,  and  whenever  handled  in  the  open  air  no 
flame  or  spark  should  be  allowed  in  the  vicinity. 

Gasoline  itself  is  not  explosive.  It  is  only  the  mixture  of 
gasoline  vapor  and  air  that  will  explode,  as  before  described. 
When  gasoline  is  handled  or  left  exposed  to  the  air  in  a  confined 
space,  such  as  a  closed  garage  or  boathouse,  evaporation,  espe- 
cially in  warm  weather,  may  cause  the  contained  air  to  be  so 
charged  with  vapor  that  the  mixture  would  be  exploded  by  a 
flame  or  spark. 

It  is  therefore  always  expedient  to  have  proper  ventilation  in 
rooms  where  gasoline  is  exposed  to  the  air  or  where  tanks 
containing  gasoline  are  stored,  the  frequent  change  of  air  carry- 
ing away  vapors  and  preventing  the  accumulation  of  a  rich 
mixture.  It  should  also  be  borne  in  mind  that  an  explosive 
mixture  of  gasoline  vapor  and  air  usually  occupies  the  space 
over  gasoline  in  a  partially  filled  tank,  which  makes  it  extremely 
dangerous  to  have  a  flame  near  when  the  tank  is  opened  for 
filling  or  for  measuring  the  contents. 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         11 

Water  should  not  be  used  in  an  attempt  to  put  out  a  gasoline 
lire,  for  the  gasoline  will  float  on  top  of  the  water  and  continue 
to  burn,  the  only  result  being  a  spreading  of  the  flames.  Sand 
or  ashes  thrown  on  the  fire  to  reduce  the  exposed  surface  of 
gasoline,  or,  better  yet,  a  good  fire  extinguisher,  the  contents  of 
which  will  generate  a  smothering  blanket  of  inert  gas,  are  the 
most  effective  means  of  subduing  the  fire. 

What  determines  the  quality  of  gasoline? — In  engineering  the 
quality  of  fuel  for  producing  power  is  usually  determined  by 
the  amount  of  heat  which  1  pound  of  that  fuel  will  produce 
when  burned.  But  with  gasoline,  as  used  in  the  modern  gas 
engine,  another  quality  is  commonly  placed  foremost.  The  ex- 
pressions "  good  gasoline "  and  "  poor  gasoline "  are  often 
heard,  also  "  high-test  "  and  "  low-test  "  gasoline.  By  "  good 
gasoline  "  and  •'  high-test  gasoline  "  is  meant  that  which  vapor- 
izes readily,  thus  causing  easy  starting  and  smooth  running  of 
a  motor.  "  Poor  gasoline  "  and  "  low-test  gasoline  "  lack  this 
quality  to  a  noticeable  extent.  It  so  happens  that  the  ease  with 
which  gasoline  is  vaporized  can  be  determined  by  comparing  the 
weight  of  a  given  volume  of  the  oil  with  an  equal  volume  of  pure 
water.  If  equal  volumes  of  different  grades  of  gasoline  were 
carefully  weighed,  that  found  to  be  lightest  would  be  best,  as 
far  as  ease  of  vaporization  is  concerned ;  the  heaviest  would 
be  poorest.  In  practice,  the  grade  of  oil  is  determined  by  means 
of  an  instrument  called  a  "  hydrometer,"  graduated  to  an  arbi- 
trary scale  called  the  "  Baume"  scale."  When  the  instrument 
is  floated  in  a  liquid  the  reading  of  the  scale  at  the  surface  is 
a  measure  of  the  relative  weight  of  the  liquid  as  compared  with 
water,  the  readings  being  higher  for  light  liquids  than  for 
heavier  ones.  Gasoline  that  tests  66°  Baume"  is  now  commonly 
considered  good.  The  lower  grades  test  about  56°  to  64°.  The 
reason  for  this  variation  in  the  quality  of  different  grades  of 
gasoline  lies  in  the  fact  that  gasoline,  like  the  crude  oil  from 
which  it  is  obtained,  is  really  a  mixture  of  several  oili. 


12         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

The  weight  of  a  given  volume  (say,  a  gallon)  of  gasoline  de- 
pends upon  the  weights  per  gallon  and  the  proportions  of  these 
separate  oils.  Since  during  distillation  the  lighter  oils  are  first 
separated  from  the  crude  product,  the  weight  per  gallon  of  the 
oils  becoming  greater  as  the  temperature  of  distillation  increases, 
it  is  evident  that  the  lower  the  temperature  and  the  narrower 
the  range  of  temperatures  over  which  the  distillation  is  allowed 
to  proceed  during  the  production  of  gasoline  the  lower  will  be 
the  weight  per  gallon  of  the  final  product.  If  the  distillation  is 
allowed  to  proceed  over  a  wide  range  of  temperatures,  the 
heavier  oils  distilled  at  the  higher  temperatures  increase  the 
weight  per  gallon  of  the  final  product,  with  a  result  that  the 
gasoline  is  heavier  and  less  readily  vaporized.  Of  course  in  the 
latter  case  the  amount  of  "  gasoline  "  produced  from  a  given 
quantity  of  crude  oil  is  much  greater  than  in  the  former. 

As  kerosene  oil  is  obtained  from  crude  oil  over  the  next  higher 
range  of  temperature  of  distillation,  oil  producers  have  used 
this  ready  means  of  regulating  their  production  of  gasoline  and 
kerosene  to  suit  the  demand.  A  few  years  ago,  when  the  con- 
sumption of  kerosene  was  enormous  as  compared  with  that  of 
gasoline,  distillation  of  the  latter  covered  a  narrow  range  of 
temperature,  and  the  quality  was  high,  as  great  in  some  cases 
as  84°  Baume".  On  the  other  hand,  as  the  recovery  of  kerosene 
was  commenced  at  a  comparatively  low  temperature,  its  weight 
per  gallon  was  consequently  low,  a  very  undesirable  quality, 
which  made  the  kerosene  vaporize  so  easily  that  it  was  some- 
what dangerous  for  domestic  use.  In  more  recent  years  con- 
sumption of  gasoline,  due  to  its  use  in  motor  vehicles,  power 
boats,  and  the  like,  has  so  increased  that  oil  producers,  in  order 
to  meet  the  demand,  have  found  it  necessary  to  broaden  more 
and  more  the  range  of  temperature  in  the  distillation  of  their 
crude  oil,  during  which  gasoline  is  produced,  thus  obtaining  a 
greater  quantity  of  heavier  grade.  One  fortunate  result,  how- 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         13 

ever,  is  the  superior  quality  of  the  kerosene  now  produced,  for, 
being  distilled  at  a  higher  range  of  temperature,  its  dangerous 
qualities  are  greatly  reduced  without  detracting  from  those  that 
make  it  useful  for  light  and  heat.  In  fact,  it  may  be  truly  said 
that  the  words  "  gasoline  "  and  "  kerosene  "  as  ordinarily  used 
to-day  hardly  mean  more  than  "  products  from  crude  oil "  suit- 
able for  the  uses  with  which  these  names  are  associated,  gasoline 
being  the  lighter  of  the  two,  but  their  exact  qualities  depending 
upon  the  relative  consumption,  the  sagacity  of  the  oil  refiners, 
and  just  how  exacting  the  public  is  in  its  demands. 


CHAPTER  III. 


DEFINITIONS  OF  WORDS  AND  TERMS  USED  WITH 
REFERENCE  TO  GASOLINE  ENGINES. 

In  many  instances  common  words  and  phrases,  when  used  in 
connection  with  gasoline  engines,  have  a  special  meaning.  This 
often  confuses  a  reader  and  makes  it  advisable,  before  going  fur- 
ther into  the  subject,  to  define  or  explain  such  of  these  words 
and  expressions  as  are  most  often  met  with. 

It  must  be  kept  in  mind  that  the  definitions  given  in  each  case 
refer  only  to  the  use  of  the  word  or  phrase  in  its  connection  with 
a  gasoline  power  plant. 

For  convenience,  an  alphabetical  arrangement  has  been 
adopted : 

Air  cooling. — A  system  of  cooling  engine  cylinders  by  means 
of  a  current  of  air. 

Alignment. — A  state  of  having  the  various  parts  of  a  machine 
in  proper  position — that  is,  "  in  line " — with  relation  to  each 
other.  When  this  proper  relationship  does  not  exist  the  parts 
are  said  to  be  "  out  of  line  "  or  "  out  of  alignment.*'  For  exam- 
ple, the  center  line  of  a  cylinder  should  lie  in  a  plane  perpen- 
dicular to  the  center  line  of  the  crank  shaft  in  order  to  be  "  In 
alignment."  Or,  as  another  example,  if  the  center  of  each  crank 
shaft  bearing  is  not  in  a  single  line  drawn  between  the  centers 
of  the  two  end  bearings,  these  bearings  are  "  out  of  alignment." 

Alternating  current.— A  current  of  electricity  that  flows 
through  the  circuit  first  in  one  direction,  then  in  the  opposite 
direction,  the  alternations  occurring  with  great  rapidity. 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         16 

Automatic  spark  advance  mechanism. — A  device,  usually  built 
on  the  principle  of  a  centrifugal  governor,  which  automatically 
changes  the  timing  of  the  spark  and  eliminates  the  necessity  of 
hand  regulation. 

Baffle,  or  baffle  plate. — A  partition  or  projection  fitted  In  a 
chamber  or  passage  to  check,  distribute,  or  change  the  direction 
of  a  current  of  gas  or  liquid. 

Battery. — A  group  of  cells  used  as  a  source  of  electricity. 
When  all  positive  terminals  are  connected  together  and  all  nega- 
tive terminals  are  connected  together,  the  cells  are  said  to  be 
connected  in  "  parallel."  When  the  positive  terminal  of  a  cell 
is  connected  to  the  negative  terminal  of  the  next  cell,  and  so 
on,  the  cells  are  said  to  be  connected  in  "  series.'*  When  a  com- 
bination of  these  two  systems  is  used  the  cells  are  said  to  be 
connected  in  "  multiple  series."  A  primary  battery  is  one  that 
can  not  be  recharged  by  passing  a  current  through  it,  an  example 
being  a  group  of  ordinary  dry  cells.  A  secondary  or  storage 
battery  is  one  which  can  be  recharged  by  causing  a  direct  current 
from  another  source  to  flow  through  it  in  the  opposite  direction 
to  that  of  the  current  generated  by  the  battery  itself.  The  cur- 
rent furnished  by  a  battery  is  always  a  direct  current. 

Bearing. — Every  part  of  a  machine  must  have  adequate  sup- 
port ;  moving  parts  must  be  so  supported  that  excessive  friction 
and  wear  will  not  be  caused  by  their  motion.  Such  a  support  is 
called  a  bearing.  Thus  a  main  shaft  bearing  consists  of  a 
frame,  usually  lined  with  antifriction  metal,  which  is  made  to 
fit  accurately,  but  not  bind  the  shaft. 

A  ball  bearing  is  one  so  arranged  that  the  shaft  or  rotating 
part  is  supported  by  steel  balls  which  in  turn  are  held  in  a 
recess  in  the  fixed  frame,  called  the  ball  race  (sometimes  the 
shaft  or  spindle  is  stationary  and  the  frame  revolves  around 
it).  Roller  bearings  are  similar  in  arrangement,  but  here  steel 
rollers  instead  of  balls  are  used.  The  principle  involved  in  the 
use  of  balls  or  .rollers  is  the  same  as  that  which  makes  it 


16         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

advisable  to  use  rollers  when  moving  any  heavy  weight,  the  force 
necessary  to  cause  rolling  generally  being  less  than  that  required 
to  cause  sliding. 

Binding  post. — A  threaded  screw  or  "post"  with  nuts  and 
lock  nuts  or  other  fastening  device  for  attaching  wires  to  elec- 
trical apparatus. 

Bloc  cylinders. — When  all  cylinders  are  cast  in  one  piece  the 
engine  is  said  to  have  "  bloc  cylinders,"  or  the  cylinders  are  cast 
"  en  bloc."  The  same  expression  is  used  whenever  groups  of 
cylinders  are  cast  in  one  piece,  and  the  total  number  of  cylinders 
is  made  up  of  two  or  more  of  these  groups,  but  in  this  case  the 
number  of  cylinders  in  a  "  bloc  "  is  usually  stated. 

Break  (as  applied  to  electrical  circuits). — The  interruption 
of  flow  of  an  electric  current  by  making  a  gap  in  the  metallic 
circuit.  Under  proper  conditions  a  hot  spark  or  "  arc  "  is  pro- 
duced at  the  point  of  break  in  the  ignitor. 

Breather. — A  passage  between  the  open  air  and  the  inside  of 
a  closed  crank  case  on  a  four-cycle  engine.  Its  purpose  is  to 
prevent  either  pressure  or  vacuum  in  the  crank  case. 

Brush. — A  device  for  making  a  good  electrical  contact  between 
a  stationary  part  and  a  moving  part  of  a  circuit.  Examples 
are:  The  brushes  of  a  dynamo  which  collect  the  current  gen- 
erated in  a  moving  armature,  or  the  brush  of  a  commutator 
which  revolves  and  comes  in  contact  with  stationary  insulated 
terminals,  thus  completing  an  electrical  circuit  at  certain  times. 

Bushing. — A  sleeve  or  collar  used  as  a  lining  for  a  bearing, 
usually  made  of  antifriction  metal. 

Cam. — An  accurately  shaped  projection  on  a  shaft  for  impart- 
ing the  necessary  motion  to  a  valve,  ignitor,  or  other  part  at 
the  proper  times. 

Cam  shaft. — The  shaft  that  carries  the  cams  for  operating 
valves  or  ignitors.  A  cam  shaft  receives  its  motion  from  the 
crank  shaft  by  means  of  spur  gear  or  silent  chain  connection. 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         17 

Carbon. — A  deposit  of  black  scale  or  soot  which  forms  on  in- 
terior walls  of  the  combustion  chamber.  It  is  caused  both  by 
the  burning  of  the  gas  and  by  the  burning  of  lubricating  oil 
which  finds  access  to  the  chamber.  The  rate  of  deposit  is  in- 
creased by  the  use  of  an  overrich  mixture  of  gas  and  by  ex- 
cessive piston  lubrication.  The  carbon  deposit  is  often  rough 
and  sometimes  peels  up  in  flakes.  The  high  portions  or  flakes 
become  red  hot  when  the  engine  is  running  and  ignite  the 
charges  of  gas  before  the  piston  has  reached  the  end  ol  its  com- 
pression stroke,  causing  a  sharp  thud  termed  the  "  carbon 
knock." 

Carburetor. — A  device  for  vaporizing  gasoline  (or  other  vola- 
tile liquid  fuel)  and  mixing  it  with  air  to  form  an  explosive 
mixture. 

Cell. — A  jar  or  case  containing  "  electrodes  "  (one  usually 
made  of  carbon,  the  other  of  zinc)  and  a  solution  of  chemicals, 
which  combination  will  generate  an  electric  current.  In  other 
words,  a  unit  of  an  electric  battery. 

Centrifugal  force. — The  tendency  of  a  body  revolving  around 
an  axle  or  shaft  to  fly  away  from  the  axle.  It  is  used  as  the 
basic  principle  of  most  governors  and  automatic  spark-advance 
mechanisms. 

Check  valve. — A  valve  which  allows  passage  of  gas  or  liquid 
through  it  in  only  one  direction. 

Circuit. — Electricity  can  flow  as  a  current  only  when  it  has 
a  loop  or  closed  path  of  conducting  material  (usually  metal) 
starting  from  the  source  of  electricity  and  leading  back  to  that 
source.  Such  a  path  is  called  a  circuit.  A  "  closed  circuit "  is 
one  that  is  complete  so  that  the  current  can  flow.  An  "  open 
circuit"  is  one  having  a  break  or  gap  (for  example,  an  open 
switch),  which  prevents  the  flow  of  current.  By  a  "short  cir- 
cuit "  is  meant  a  connection  (either  accidental  or  intentional) 
76616°—17 2 


18         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

which  allows  the  current  to  take  a  "  short  cut "  from  some  part 
of  the  regular  circuit  back  to  the  source. 

Circulating  pump. — When  a  water-cooling  system  is  used  some 
means  must  be  employed  to  cause  the  water  to  circulate  through 
the  cooling  jackets.  A  pump  used  for  this  purpose  is  called  a 
circulating  pump.  Likewise,  when  forced-feed  lubrication  is 
used,  a  pump  for  forcing  the  oil  through  the  system  is  called  an 
oil-circulating  pump. 

Closed  circuit. —  (See  Circuit.) 

Clutch. — A  coupling  between  two  parts  of  a  machine  so  ar- 
ranged that  when  it  is  "  thrown  out "  one  part  can  operate  inde- 
pendently of  the  other  part  (in  other  words,  they  are  discon- 
nected), when  "thrown  in"  the  parts  are  held  together,  one 
usually  driving  the  other.  In  connection  with  gasoline  engines, 
a  clutch  is  often  used  to  readily  connect  or  disconnect  the  en- 
gine from  its  load  without  stopping  the  engine.  It  is  always 
used  on  gasoline  vehicles,  for  without  it  the  engine  could  never 
be  started  without  the  vehicle  starting  at  the  same  time. 

Coil. — The  induction  coil  used  in  ignition  systems  is  usually 
spoken  of  simply  as  the  "coil."  (See  "Induction  coil.") 

Combustion. — The  burning  of  the  gasoline  mixture.  This 
burning  takes  place  with  such  rapidity  that  it  is  termed  an  ex- 
plosion. (See  Chapter  II.) 

Commutator. — A  device  forming  part  of  the  primary  circuit 
of  an  ignition  system,  which  "  closes  "  and  "  opens  "  this  circuit 
in  such  a  manner  that  sparks  are  caused  at  the  proper  times  in 
each  cylinder. 

Compression. — After  a  charge  of  mixture  has  been  introduced 
into  the  cylinder  its  volume  is  reduced  and  its  pressure  is  in- 
creased by  the  movement  of  the  piston  toward  the  cylinder  head. 
This  action  is  called  "  compression." 

While  the  piston  is  moving  toward  the  cylinder  head,  causing 
compression  of  the  mixture,  it  is  said  to  be  making  the  "  com- 
pression stroke." 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         19 

When  a  leak  from  the  combustion  space  (past  a  loose  or 
poorly  fitted  piston,  through  a  leaky  valve  or  defective  spark 
plug,  or  in  any  other  way)  allows  such  an  escape  of  mixture 
that  a  proper  compression  of  the  mixture  is  not  obtained,  the 
cylinder  is  said  to  have  "  poor  compression  "  or  "  has  lost  its 
compression." 

Connecting  rod. — The  bar  which  connects  the  piston  to  the 
crank.  It  is  fitted  with  a  bearing  at  each  end. 

Contact  points. — The  points  in  vibrators  or  other  forms  of  in- 
terrupters where  the  electric  circuit  is  "  made  "  and  "  broken." 
Ordinarily  they  are  not  actually  points,  but  small,  flat  buttons 
made  of  platinum,  platinum-iridium  alloy,  tungsten,  or  other 
material  well  adapted  for  resisting  extreme  heat  and  the  de- 
structive action  of  the  electric  spark. 

Control. — The  levers,  links,  switches,  etc.,  by  which  the  regu- 
lation of  the  engine  is  accomplished  is  called  the  "  control." 

Cooling  fins  or  flanges. — The  ribs  or  projections  used  on  air- 
cooled  cylinders  and  radiators  for  the  purpose  of  increasing  the 
surface  from  which  heat  may  radiate. 

Cooling  jacket. — The  chamber,  surrounding  the  cylinder  and 
valve  recesses  of  a  water-cooled  engine,  through  which  the  cool- 
ing water  is  circulated. 

Crank. — The  offset  part  of  the  shaft  where  the  connecting  rod 
is  attached  bj;  means  of  a  bearing.  (Also  the  handle  by  which 
an  engine  is  started  by  hand.) 

Crank  case.— The  casing  which  incloses  the  space  around  the 
crank.  Various  other  parts  are  also  located  within  this  inclosure. 

Cranking. — The  act  of  turning  an  engine  to  accomplish  start- 
ing. 

Crank  shaft. — The  main  shaft  of  the  engine  which  carries  the 
cranks. 

Cup  (grease  or  oil). — A  small  vessel  or  recess  for  holding  a 
supply  of  lubricant.  They  are  usually  so  arranged  that  the 
supply  of  oil  or  grease  is  fed  gradually  to  the  surface  lubricated. 


20         CAKE  AND  OPERATION  OF  GASOLINE  ENGINES. 

Current. — The  flow  of  electricity  around  a  circuit. 

Cylinder. — That  part  of  the  engine  (usually  an  iron  casting) 
in  which  the  piston  moves  to  and  fro. 

Cylinder  head. — The  cover  which  closes  that  end  of  the  cylin- 
der which  is  farthest  from  the  crank.  Sometimes  the  head  is 
part  of  the  cylinder  casting,  but  the  present  tendency  is  to  make 
it  a  separate  part,  fastened  to  the  cylinder  by  bolts.  With  a 
removable  head  cleaning  of  the  combustion  chamber  and  inspec- 
tion of  the  interior  of  the  cylinder  are  more  easily  accomplished 
than  when  the  head  is  cast  on  the  cylinder. 

Cycle. — In  general,  the  word  "  cycle  "  means  a  series  of  events 
occurring  in  regular  order  and  ending  with  all  conditions  in  the 
same  state  as  that  which  existed  at  the  beginning,  whereupon 
another  cycle  begins.  With  particular  reference  to  a  gasoline 
engine,  a  cycle  means  that  series  of  operations  which  takes  place 
in  producing  one  power  impulse.  The  words  "  two-cycle  "  and 
"  four-cycle  "  in  themselves  really  have  no  meaning.  They  were 
unfortunately  coined  by  early  inventors  to  signify  the  number 
of  strokes  the  piston  of  their  engines  made  in  producing  one 
explosive  impulse.  Thus  when  the  piston  makes  two  strokes 
for  each  explosion  (or  to  complete  a  cycle)  the  engine  is  said  to 
be  of  the  "  two-cycle  "  type ;  when  four  strokes  of  the  piston  are 
required  to  produce  one  explosion,  the  engine  is  of  the  "four- 
cycle "  type.  From  the  above  it  is  apparent  that  a  stroke  is  not  a 
cycle,  as  is  often  supposed  and  sometimes  stated  in  books  of 
instructions. 

To  avoid  the  confusion  caused  by  these  terms  some  authorities 
distinguish  between  the  two  types  by  calling  them  "  two-stroke  " 
and  "  four-stroke " ;  others  call  them  "  two-stroke  cycle "  and 
"  four-stroke  cycle  "  engines. 

Displacement,  piston. — By  piston  displacement  is  meant  the 
difference  between  the  volume  of  space  within  the  cylinder 
when  the  piston  is  at  tlie  head  end  of  its  stroke  and  the 


CARE  AND  OPERATION  OP  GASOLINE  ENGINES.         21 

volume  of  space  when  the  piston  is  at  the  crank  end.  It  is 
equal  to  the  cross-sectional  area  of  the  cylinder  measured  in 
square  inches,  multiplied  by  the  length  of  the  stroke  measured 
in  inches. 

Distributor. — An  automatic  electrical  device  for  directing  the 
igniting  current  to  the  various  cylinder  spark  plugs  at  the  proper 
times.  It  operates  in  much  the  same  manner  as  a  commutator, 
but  is  so  designed  that  it  will  handle  the  high  tension  current. 

Dowel  or  "  dowel  pin." — A  pin  for  the  purpose  of  holding  two 
or  more  parts  of  a  machine  in  an  exact  position  while  the  per- 
manent fastening  is  made  by  means  of  bolts  or  screws.  Dowels 
are  often  so  arranged  as  to  make  it  impossible  to  assemble  the 
parts  except  in  their  proper  relative  positions.  One  end  of  the 
pin  is  permanently  fastened  in  one  part  of  the  machine,  the 
other  end  fitting  neatly  into  a  hole  in  the  other  part. 

Drain  cock. — A  faucet  or  valve  fitted  in  the  lower  part  of 
water  chambers,  radiators,  carburetors,  tanks,  etc.,  for  emptying 
or  "  draining  "  these  chambers. 

Dual  ignition  system. — Two  systems  of  ignition,  more  or  less 
independent,  fitted  to  an  engine  so  that  either  can  be  used  for 
generating  the  sparks  is  called  a  dual  system.  As  a  general 
thing  batteries  and  coil  are  used  for  starting,  or  in  case  of  emer- 
gency, and  a  magneto  used  for  regular  running.  When  two  sets 
of  spark  plugs  are  used,  and  the  system  so  arranged  that  for 
regular  running  a  spark  is  produced  at  both  plugs  of  each  cylin- 
der for  every  explosion,  the  system  is  said  to  be  "  double,"  or 
"  two-point."  A  combination  of  these  two  arrangements  is  a 
"  double  dual  ignition  system." 

Dynamo. — An  electric  generator  geared  or  belted  to  the  en- 
gine and  used  to  furnish  current  for  ignition,  charging  batteries, 
lighting,  etc. 

Electrode. — The  two  "  elements  "  or  plates  of  a  battery  cell 
are  the  electrodes.  The  positive  plate  or  terminal — that  is,  the 


22         CAFJE  AND  OPERATION  OF  GASOLINE  ENGINES. 

one  through  which  the  current  flows  from  the  cell — is  called  the 
"  anode."  The  one  through  which  the  current  returns  to  the 
cell  is  called  the  "  cathode." 

Electrolyte. — The  electrodes  of  a  cell  are  immersed  in  a  liquid 
called  the  "  electrolyte."  The  chemical  action  between  electrodes 
and  electrolyte  generates  an  electric  current. 

En  Hoc  cylinders. —  (See  "bloc  cylinders.") 

Exhaust. — The  discharge  or  escape  of  burnt  gases  from  the 
cylinders. 

Exhaust  valve. — The  valve  through  which  the  burnt  gases 
escape  from  a  cylinder. 

Explosion. — The  violent  combustion  or  burning  of  the  mixture 
of  gasoline  vapor  and  air. 

Factor-of-safety. — The  numerical  ratio  between  the  strength  of 
any  part  of  an  engine  and  the  force  which  this  part  is  required 
to  resist.  When  an  engine  is  spoken  of  as  having  "  a  general 
factor  of  safety  of  12,"  it  is  meant  that  the  strain  necessary  to 
break  any  part  is  at  least  12  times  as  great  as  the  actual  strain 
that  the  particular  part  sustains  when  in  operation. 

Fan. — The  air  propeller  used  to  cause  rapid  passage  of  air 
through  the  radiator  or,  on  an  air-cooled  engine,  around  the 
cylinders. 

Firing  order. — In  a  multiple-cylinder  engine,  after  an  explo- 
sive impulse  is  delivered  in  one  cylinder,  each  of  the  other  cylin- 
ders delivers  an  impulse  before  the  next  explosion  takes  place 
in  the  first  cylinder,  and  these  impulses  occur  in  regular  order, 
determined  by  the  angles  of  the  cranks  on  the  shaft.  The  order 
in  which  the  impulses  follow  one  another  in  the  various  cylin- 
ders is  usually  spoken  of  as  the  firing  order. 

Float. — Carburetors  of  the  "  float-feed  "  type  have  a  small 
reservoir  in  which  a  constant  level  of  gasoline  is  maintained. 
The  cork  block  or  metal  drum  which  floats  in  this  gasoline  and 
automatically  controls  the  inlet  needle  valve  is  called  the 
"  float." 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         23 

Flywheel. — The  heavy  wheel  usually  carried  on  one  end  of 
the  crank  shaft.  By  virtue  of  its  weight,  it  causes  steady  opera- 
tion of  the  engine. 

Friction. — The  resistance  which  must  be  overcome  to  cause 
motion  between  two  parts  in  contact  with  each  other.  Oil 
reduces  this  resistance  by  forming  a  liquid  coat  on  the  surfaces 
and  preventing  close  contact. 

Gap. — The  space  between  the  points  of  a  spark  plug  across 
which  the  current  jumps  in  forming  the  spark.  The  "  circuit " 
is  "  open  "  at  this  gap,  there  being  no  metallic  conductor  for  the 
current.  It  is  high  voltage  that  enables  the  current  to  over- 
come the  resistance  encountered  at  the  gap. 

Gas. — The  mixture  of  gasoline  vapor  and  air  is  often  spoken 
of  simply  as  the  "  gas."  This  word  is  also  sometimes  used  as  a 
short  term  for  gasoline  in  the  liquid  form. 

Gasket. — A  layer  of  comparatively  soft  elastic  material  used 
between  metal  parts  to  form  a  tight  joint.  .  A  common  form  of 
gasket  consists  of  a  sheet  of  asbestos  packing  cut  to  proper 
shape  to  fit  the  joint  and  covered  by  a  casing  of  very  thin  sheet 
copper  or  brass. 

Gears. — Toothed  wheels  which,  through  the  engagement  of 
their  teeth,  transmit  motion  from  one  wheel  to  the  other. 
When  the  motion  is  transmitted  through  several  gears  the  com- 
bination is  called  a  "  train  of  gears  "  or  a  "  gear  train." 

"  Half-time  gears "  are  those  that  transmit  motion  to  the 
cam  shaft  in  such  a  way  that  this  shaft  will  make  one  revolu- 
tion while  the  crank  shaft  makes  two.  When  the  axes  about 
which  a  pair  of  gear  wheels  revolve  do  not  lie  parallel  to  each 
other  the  teeth  have  to  be  tapered  and  cut  at  an  angle  (one 
side  of  the  wheel  is  smaller  than  the  other).  They  are  then 
called  "  bevel  gears."  The  smaller  of  two  or  more  gears  of  a 
set  is  called  the  "  pinion." 

Recently,  for  high-class  work,  it  has  become  the  practice  to 
cut  half-time  gears  so  that  their  teeth  are  at  an  angle  instead 


24         CARE  AND  OPERATION  OP  GASOLINE  ENGINES. 

of  straight.  This  causes  the  teeth  to  engage  gradually  and 
does  away  with  much  of  the  usual  noise  and  vibration  that 
attends  the  use  of  plain  gears.  When  the  teeth  are  cut  in  this 
manner  the  gears  are  said  to  be  "  helical."  Sometimes  bevel 
gears  are  made  with  helical  teeth. 

A  "  worm  gear  "  consists  of  a  pinion  with  teeth  so  cut  that 
they  wind  around  the  axis  in  the  form  of  a  screw  engaged  with 
a  wheel  having  teeth  properly  shaped  to  "  mesh  "  with  this  screw. 

Generator. —  (See  Dynamo.) 

Governor. — A  device  which  automatically  operates  the  throttle 
when  the  engine  is  running  and  regulates  or  limits  the  speed. 

Graphite. — A  solid  form  of  lubricant,  usually  mixed  with 
grease  or  oil,  for  reducing  the  friction  of  gears. 

Ground  (electrical). — An  electrical  connection  in  any  part  of 
a  circuit  to  the  body  or  base  of  the  engine.  It  may  be  intentional 
or  accidental.  Two  "  grounds  "  often  produce  a  "  short  circuit." 

Half-time  shaft. — A  cam  shaft  which  makes  one  revolution 
while  the  crank  shaft  makes  two.  (Cam  shaft  of  a  four-cycle 
engine. ) 

High  tension  or  high  voltage. — As  used  in  connection  with 
gasoline-engine  ignition  this  expression  means  "  tension "  or 
"  voltage  "  sufficiently  high  to  cause  the  current  to  jump  across 
the  gap  in  a  spark  plug. 

Hot-air  pipe. — A  passage  or  pipe  which  conducts  heated  air 
to  the  carburetor.  The  heated  air  is  usually  drawn  from  a 
jacket  around  the  exhaust  pipe. 

Hydrometer. — A  graduated  float  used  for  measuring  the 
weight  of  a  liquid  as  compared  to  the  weight  of  an  equal 
volume  of  pure  water.  (See  p.  11.) 

Ignition. — The  complete  system  which  generates  the  sparks  for 
exploding  the  charges  of  gas  is  often  spoken  of  as  the  "  ignition." 

Induced  current. — The  electric  current  which  flows  through 
the  secondary  circuit  of  an  induction  coil.  It  Is  produced  by 
the  action  of  another  current  flowing  through  the  primary 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         25 

circuit.  The  secondary  circuit  is  high  tension;  the  primary  is 
low  tension. 

Induction  coil. — The  device  in  which  a  "  low- voltage  "  current 
is  transformed  into  a  high-tension  current.  For  jump-spark 
ignition  a  coil  has  two  separate  windings — the  "  primary  "  or 
low- voltage  winding  being  a  comparatively  few  turns  of  fairly 
coarse  insulated  wire,  the  "  secondary  "  or  high-tension  winding 
having  many  turns  of  fine  wire. 

The  current  in  the  primary  coil  induces  a  high-tension  cur- 
rent in  the  secondary  coil,  hence  the  name  "  induction  coil." 

Inlet  valve. — The  valve  through  which  the  charges  of  gas  are 
admitted  to  the  cylinder. 

Insulation. — The  nonconducting  material  used  as  a  covering 
for  electric  wires  or  to  separate  any  part  of  a  circuit  from  con- 
tact with  conducting  material  which  is  not  a  part  of  the  circuit. 

Interruptor. — A  device  which  rapidly  makes  and  breaks  an 
electrical  circuit.  The  magnetic  vibrator  is  the  most  common 
form  of  interruptor. 

Jump  spark. — The  common  name  for  the  spark  generated  by 
a  high-tension  current  leaping  across  the  gap.  High-tension 
ignition  is  often  called  "jump-spark  ignition." 

Key. — A  suitably  shaped  piece  of  metal,  usually  steel,  fitted 
in  a  slot  or  recess,  part  in  the  shaft  and  part  in  the  wheel,  cam, 
sleeve,  or  other  device  carried  on  the  shaft.  Its  purpose  is  to 
fasten  these  parts  on  the  shaft.  A  sliding  key  or  "feather" 
is  one  so  fitted  that  the  part  carried  on  the  shaft  can  move 
lengthwise  but  can  not  revolve  except  as  the  shaft  revolves. 

Knock. — The  regularly  repeated  jar  or  thumping  sound  caused 
by  a  loose  bearing,  or  other  poorly  fitted  or  loose  working  part. 
A  "  carbon  knock  "  is  one  caused  by  preignition,  due  to  exces- 
sive carbon  deposit  in  the  combustion  chamber. 

L-head  engine.— An  engine,  the  cylinder  of  which  has  inlet 
and  exhaust  valves  located  on  one  side  of  the  combustion 
chamber. 


26         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

Liner. — A  thin  layer  of  suitable  material  (usually  metal) 
placed  between  the  two  halves  of  an  adjustable  bearing  to  pre- 
vent too  close  contact  between  the  bearing  metal  and  the  pin 
or  shaft.  Liners  are  sometimes  called  "  shims." 

Low-tension  (low  voltage). — With  reference  to  gasoline- engine 
ignition  "  low  tension  "  means,  suitable,  as  regards  voltage,  for 
use  with  a  "  make-and-break  "  ignition  system. 

Lubricant. — Any  substance  used  to  coat  the  surface  of  bear- 
ings for  the  purpose  of  reducing  friction  between  parts  that 
rub  one  upon  the  other. 

Lubrication. — The  act  or  process  of  furnishing  lubricant  to 
bearing  surfaces. 

Magneto. — An  electric  generator  especially  designed  for  gas- 
engine  ignition.  It  differs  from  a  dynamo  in  that  the  current 
is  intermittent,  being  furnished  only  at  the  time  a  spark  is  re- 
quired. For  this  reason  a  magneto  has  to  be  so  connected  to  the 
engine  that  its  armature  will  be  driven  at  a  speed  proportionate 
to  the  engine  speed,  and  so  set  that  a  current  is  generated  at 
the  proper  instants  for  ignition.  "  Timing "  a  magneto  means 
setting  the  armature  so  that  the  above  conditions  are  achieved. 

Because  of  the  intermittent  nature  of  the  current  produced 
by  a  magneto,  these  machines  are  not  suitable  for  lighting  elec- 
tric lamps  or  charging  storage  batteries. 

A  high-tension  magneto  is  one  that  produces  current  at  suffi- 
ciently high  voltage  to  cause  it  to  jump  the  gap  of  a  spark 
plug. 

A  low-tension  magneto  produces  a  current  at  comparatively 
low  voltage.  This  low-tension  current  has  to  be  transformed  to 
high-tension  current  by  use  of  an  induction  coil  if  the  jump 
spark  is  used. 

Low-tension  magnetos  are  sometimes  used  to  furnish  current 
for  "make-and-break"  ignition. 

Make-and-break  ignition. — An  ignition  system  using  a  low- 
tension  current  and  generating  a  spark  by  breaking  the  circuit 


CARE  AND  OPEEATION  OF  GASOLINE  ENGINES.         27 

within  the  combustion  chamber  at  the  proper  time  for  ignition 
of  each  charge. 

Manifold. — A  pipe  or  passage  having  two  or  more  branches 
leading  to  like  ports  or  chambers  of  the  several  cylinders  on 
multiple-cylinder  engines.  The  two  principal  manifolds  on  an 
engine  are  the  inlet  manifold  for  conducting  mixture  from  the 
carburetor  to  the  cylinders,  and  the  exhaust  manifold  for  lead- 
ing the  exhaust  from  the  separate  cylinders  into  a  common 
exhaust  pipe. 

Missing. — When  the  proper  impulses  fail  to  take  place  regu- 
larly in  one  or  more  cylinders  the  engine  is  said  to  be  "  missing." 
To  "  find  which  cylinder  is  missing "  means  determining  in 
which  cylinder  the  explosions  do  not  occur  either  with  regu- 
larity or  at  all.  A  word  commonly  used  by  motorists  is  "  hit- 
ting," meaning  the  opposite  of  missing.  As  an  example:  Sup- 
pose four  cylinders  of  a  six-cylinder  engine  are  working  prop- 
erly, while  the  other  two  cylinders  do  not  deliver  their  power 
impulses  regularly,  then  the  four  cylinders  are  said  to  be  hitting, 
the  two  cylinders  are  missing. 

Mixture. — The  mixture  of  gasoline  vapor  and  air  as  fur- 
nished by  a  carburetor  is  usually  called  simply  "  mixture." 

A  "  lean  mixture "  is  one  that  has  a  comparatively  large 
proportion  of  air  as  compared  with  the  proportion  of  gasoline 
vapor.  A  mixture  having  a  comparatively  large  proportion  of 
gasoline  is  called  a  "  rich  mixture." 

Muffler. — A  device  for  silencing  or  reducing  the  noise  of  the 
exhaust. 

Needle  valve. — A  valve  capable  of  close  adjustment  so  that  a 
very  small  amount  of  gas  or  liquid  can  flow  through. 

Oil  groove. — A  channel  cut  in  a  bearing  surface  to  aid  in  the 
distribution  of  lubricant. 

Oil  sump. — A  reservoir  usually  formed  in  the  lower  part  of 
the  crank  case  or  sub-base,  from  which  lubricating  oil  is  circu- 
lated to  bearings  and  to  which  it  returns  for  recirculation. 


28         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

Open  circuit. —  (See  Circuit.) 

Piston. — The  cylindrical  casting,  together  with  its  packing 
rings,  which  slides  to  and  fro  in  the  cylinder. 

Piston  ring. — A  spring  or  ring  neatly  fitted  in  a  groove  around 
the  piston  body  to  form  a  tight  joint  between  the  piston  body 
and  the  cylinder. 

Piston  pin. — The  pin,  carried  in  the  piston  body  for  forming 
the  movable  joint  between  the  piston  and  the  connecting  rod. 
This  pin  is  also  sometimes  called  a  wrist  pin,  gudgeon  pin,  or 
crosshead  pin. 

Port. — An  opening  for  passage  of  gases  into  or  out  of  a 
cylinder. 

Preignition. — Explosion  of  the  charge  before  the  proper  time. 

Primary  circuit. — The  low-tension  circuit  of  a  jump-spark 
ignition  system. 

Priming  a  cylinder. — Introducing  liquid  gasoline  into  a  cyl- 
inder or  inlet  manifold  to  facilitate  starting. 

Priming  cock. — A  pet  cock  with  a  cup-shaped  nozzle,  so  fitted 
to  the  combustion  chamber  that  it  can  be  used  to  introduce 
liquid  gasoline  directly  into  this  space.  They  are  also  some- 
times called  "  relief  cocks  "  since  they  furnish  a  means  of  re- 
leasing part  of  the  charge  as  it  is  compressed,  thus  reducing 
the  force  required  to  turn  the  engine  in  starting. 

Pump. — A  device  for  causing  a  flow  of  gas  or  liquid,  usually 
through  pipes  or  passages.  The  three  types  of  pump  most  used 
in  gasoline  engines  are: 

(a)  Plunger  pumps,  having  a  piston  or  "plunger"  working 
in  a  cylinder  and  check  valves  properly  arranged  to  direct  the 
flow. 

(&)  Centrifugal  pumps,  having  a  bladed  wheel,  or  "  impeller," 
somewhat  like  a  paddle  wheel,  which  revolves  in  a  chamber  or 
casing. 

(c)  Gear  pumps,  in  which  the  flow  is  induced  by  the  action  of 
the  teeth  of  gear  wheels  working  in  a  casing. 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         29 

Push  rod. — A  rod  or  pin  operated  by  a  cam,  which  transmits 
the  cam  motion  to  another  part  of  the  engine. 

Radiator. — The  chamber  or  system  of  passages  through  which 
cylinder  cooling  water  is  circulated  to  reduce  its  temperature. 

Retarding  the  spark. — Nearly  all  engines  have  the  ignition 
mechanism  so  arranged  that  the  time  at  which  the  spark  occurs 
in  the  cylinder  can  be  regulated  while  the  engine  is  running. 
When  the  adjustment  is  such  that  the  spark  occurs  just  at  the 
end  of  the  compression  stroke  or  a  little  thereafter  it  is  said  to 
be  "  retarded." 

Scores. — Scratches  or  grooves  worn  in  the  bearing  surfaces 
as  a  result  of  poor  lubrication.  The  bearing  surfaces  of  pistons 
and  the  cylinder  bore  are  especially  liable  to  score  unless  prop- 
erly lubricated  and  kept  free  of  carbon  or  other  gritty  matter. 

Secondary  circuit. — The  high  tension  circuit  of  a  jump-spark 
ignition  system,  fitted  with  induction  coil. 

Sediment  trap. — A  bulb  or  pocket  in  a  pipe  line  so  located 
that  dirt  and  solid  matter  settle  in  this  chamber  instead  of  being 
carried  on  through  the  piping.  It  is  usually  equipped  with  a 
strainer  and  arranged  to  be  readily  cleaned. 

Series  connections. — A  method  of  connecting  the  various 
parts  of  an  electrical  circuit  end  to  end,  forming  a  single  path 
for  the  current. 

Shaft. — Any  cylindrical  bar,  which  transmits  motion  from 
one  part  of  a  machine  to  another  part  by  virtue  of  a  rotary 
motion  about  its  own  center  line,  is  called  a  "  shaft."  Various 
devices  such  as  cranks,  eccentrics,  cams,  etc.,  when  fitted  to  a 
shaft  are  usually  included  by  the  term  "  shaft."  In  a  gasoline 
engine  the  principal  shafts  are  the  crank  shaft  and  the  cam 
shaft. 

Short  circuit. —  (See  Circuit.) 

Spark. — The  hot,  brilliant  glow  caused  by  the  electric  current 
when  the  points  of  a  make-andLbreak  ignition  plug  are  separated, 
or  wlien  a  high  tension  current  jumps  the  gap  of  a  spark  plug. 


30         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

Spark  advance. — To  obtain  economical  and  satisfactory  work- 
ing of  an  engine  it  is  necessary  to  so  regulate  the  time  at  which 
the  spark  is  made  that  it  occurs  earlier  in  the  cycle  when  the 
engine  is  running  at  high  speed  than  when  at  slow  speed.  This 
regulation  is  usually  accomplished  by  hand  through  a  system  of 
links  and  levers  (the  "  spark  advance  mechanism  ").  This  same 
mechanism  is  used  for  "  retarding  the  spark." 

Spark  plug. — By  "  spark  plug  "  is  usually  meant  the  ordinary 
"  high-tension "  plug,  consisting  of  a  threaded  metal  shell  in- 
casing an  insulated  spindle.  The  gap  is  between  this  spindle 
and  a  pin  fastened  to  the  outer  shell.  The  plug  or  plate  which 
carries  the  movable  latch  and  insulated  pin  for  a  "  make-and- 
break  "  spark  is  sometimes  called  a  spark  plug,  but  more  often 
an  "  ignitor  plug,"  or  simply  "  ignitor." 

Springs,  valve. — In  four-cycle  engines  the  valves  are  usually 
opened  by  cams  which  operate  the  push  rods,  these,  in  turn, 
pushing  the  valve  stems  and  lifting  the  valves  from  their  seats. 
The  return  motion,  or  closing  of  the  valve,  is  accomplished  by 
steel  coiled  springs,  called  "  valve  springs." 

Starter. — The  mechanism  by  which  the  working  parts  of  the 
engine  are  set  in  motion  to  accomplish  starting.  A  hand  starter 
usually  consists  of  a  hand  crank  which  engages,  through  a 
ratchet,  with  the  crank  shaft  in  such  a  way  that  the  engine  can 
be  turned  in  the  proper  direction  and  the  crank  is  pushed  out  of 
engagement  when  the  engine  begins  to  run  under  its  own  power. 
When  the  engine  is  started  by  other  than  manual  effort,  it  is 
said  to  be  self-starting,  and  the  mechanism  is  called  a  self- 
starter. 

Strainer. — A  screen  used  as  a  trap  for  dirt  and  sediment  in  oil 
or  gasoline  pipes. 

Stroke. — By  the  stroke  of  an  engine  is  usually  meant  the  linear 
distance  the  piston  moves  in  one  direction.  This  distance  is 
equal  to  twice  the  "  throw  of  the  crank  "  arid  is  expressed  in 
inches.  The  term  "  stroke  "  is  also  used  to  denote  the  movement 


CARE  AND  OPERATION  OP  GASOLINE  ENGINES.         31 

of  the  piston  in  one  direction ;  thus,  in  a  four-cycle  engine,  by 
suction  "  stroke  "  is  meant  the  movement  of  the  piston  during 
which  a  charge  of  mixture  is  drawn  into  the  cylinder ;  the  com- 
pression "  stroke "  is  that  during  which  the  charge  is  com- 
pressed ;  the  expansion  "  stroke  "  that  during  which  the  charge 
burns  and  power  is  delivered ;  and  the  exhaust  "  stroke  "  that 
during  which  the  burnt  gases  are  discharged  from  the  cylinder. 
(See  "Cycle.") 

Sump. —  (See  "  Oil  sump.") 

Switch. — An  electrical  device  used  to  open  or  close  a  circuit. 

Tension. — Same  as  "  Voltage." 

T-liead. — A  four-cycle  engine  having  inlet  valves  on  one  side 
of  the  combustion  chamber  and  exhaust  valves  on  the  other  side 
is  called  a  "  T-head  engine." 

Tliermo-siphon  cooling. — A  water-cooling  system  so  arranged 
that  circulation  is  caused  by  the  difference  in  the  weight  of 
equal  volumes  of  water  at  different  temperatures. 

Three-port  engine.— A  two-cycle  engine  having  three  ports  in 
the  cylinder  walls. 

Timer. — For  successful  operation  the  igniting  spark  must 
always  take  place  when  the  piston  has  reached  a  certain  point 
in  the  cycle ;  this  point  varies  somewhat,  according  to  the  speed 
of  the  engine.  That  part  of  the  ignition  apparatus  which  deter- 
mines the  time  at  which  the  spark  occurs  is  often  called  the 
"timer." 

Timing. — The  act  of  so  adjusting  or  setting  a  timer  that  proper 
ignition  results  is  called  "  timing  "  the  ignition.  The  adjustment 
of  the  cam-shaft  gearing  is  called  "  timing  "  the  cam  shaft. 

Transformer. —  (See  Induction  coil.) 

Two-port  engine. — A  two-cycle  engine  which  has  but  two  ports 
in  the  cylinder  walls. 

Vacuum. — A  vacuum  is  said  to  exist  in  a  chamber  when  the 
contained  gases  are  rarefied ;  that  is,  reduced  to  a  pressure  below 
that  of  the  atmosphere. 


32         CARE  AND  OPERATION  OP  GASOLINE  ENGINES. 

Valve. — A  device  for  'opening  or  closing  a  passage  through 
which  liquids  or  gases  flow,  or  for  regulating  the  flow  of  these 
substances  through  a  passage. 

"  Valve-in-head." — When  the  valves  of  a  four-cycle  engine  are 
fitted  directly  in  the  head  of  the  cylinder  the  engine  is  said  to 
be  of  the  "  valve-in-head  "  type.  This  construction  is  used  to 
reduce  the  wall  surface  of  the  combustion  chamber. 

Valve  lifter. — A  tool  for  removing  valve  springs.  Valve  "  push 
rods  "  are  sometimes  called  valve  lifters. 

Valve  seat. — The  finished  surface  against  which  the  disk  of 
a  valve  presses  to  form  a  tight  joint  and  close  the  passage. 

Valve  stem.^-The  rod  on  which  the  valve  disk  is  carried  and 
by  which  it  is  lifted  from  and  drawn  to  its  seat.  Usually  the 
valve  disk  and  stem  are  integral ;  that  is,  a  single  piece  of  metal. 

V  arrangement  of  cylinders. — With  engines  having  more  than 
six  cylinders  the  customary  practice  is  to  install  the  cylinders 
in  two  sets  of  equal  numbers,  the  two  sets  being  inclined  at  a 
suitable  angle  in  the  form  of  a  V.  Two-cylinder  motorcycle 
engines  usually  have  cylinders  arranged  in  this  manner. 

Vaporizer. — This  word  is  sometimes  used  with  the  same  mean- 
ing as  the  word  carburetor,  especially  with  reference  to  car- 
buretors of  the  simpler  type. 

Voltage. — The  electrical  pressure  which  causes  a  current  of 
electricity  to  flow  through  a  conductor. 

Water-cooling  system. — A  system  for  preventing  too  high 
temperature  of  cylinder  walls  by  circulating  water  through  cham- 
bers surrounding  these  walls. 

Wiring. — The  insulated  conductors  or  wires  used  to  connect 
the  various  parts  of  an  ignition  system  and  form  the  various 
circuits  is,  as  a  whole,  called  the  wiring. 

Wiring  diagram. — A  sketch  or  plan  showing  the  electrical  con- 
nections of  the  apparatus  which  comprises  the  ignition  system. 

Worm  gear. — (See  "  Gear,") 


CHAPTER  IV. 


HOW  A  GASOLINE  ENGINE  WOKKS. 

A  gasoline  engine  is  a  machine  in  which  the  power  of  an 
explosive  mixture  of  gasoline  vapor  and  air  is  used  to  produce 
rotary  motion  of  a  shaft.  From  this  shaft  the  power  can  be 
transmitted  to  the  apparatus  which  is  to  do  the  useful  work. 

Without  taking  info  account  engines  of  unusual  design  and 
those  working  on  the  turbine  principle,  still  in  the  experimental 
stage  of  development,  there  are  in  use  to-day  a  vast  number  of 
makes  of  gasoline  engines,  some  differing  so  much  in  appear- 
ance and  details  that  it  seems  quite  impossible  that  all  operate 
on  the  same  general  principle.  But  in  practically  all  gasoline 
engines  now  manufactured  the  following  series  of  operations 
takes  place.  Gasoline  from  the  supply  tank  is  carried  by 
piping  to  a  vaporizing  apparatus,  usually  called  a  carburetor. 
Here  the  gasoline  is  converted  into  vapor  and  mixed  with  a 
proper  proportion  of  air,  forming  the  explosive  mixture.  A 
charge  of  this  mixture  is  compressed  in  the  engine  cylinder  by 
motion  of  the  piston  toward  the  cylinder  head.  When  the  piston 
is  at  or  near  the  end  of  its  compression  stroke  the  charge  is 
ignited  and  burns,  the  resulting  pressure  driving  the  piston 
away  from  the  cylinder  head,  and  by  means  of  a  connecting 
rod  and  crank  causing  rotary  motion  of  the  crank  shaft  and 
flywheel.  The  weight  of  the  flywheel  keeps  the  shaft  in  motion 
until  another  charge  is  compressed  and  exploded,  thus  causing 
continuous  operation. 

Two  distinct  types  of  engines  have  been  developed,  both 
operating  as  explained  above,  but  differing  in  the  method  used 
for  introducing  fresh  charges  of  gas  into  the  cylinder.  These 
76616°— 17 3  33 


34         CAKE  AND  OPERATION  OF  GASOLINE  ENGINES. 

two  types  of  engines  are  designated  as  two-cycle  and  four-cycle, 
because  in  the  former  a  complete  series  of  events  (technically 
called  a  cycle)  necessary  to  produce  one  power  stroke  takes 
place  during  two  strokes  of  the  piston,  while  in  the  latter  four 
strokes  of  the  piston  are  required  for  each  power  stroke. 

From  a  mechanical  standpoint  the  two-cycle  engine  is  mucn 
less  complicated  than  the  four-cycle.  From  a  theoretical  point 
of  view  the  four-cycle  is  somewhat  the  simpler,  since  in  this 
type  the  gases,  both  before  and  after  combustion,  are  handled 
only  in  the  cylinder  space,  while  the  two-cycle  principle  necessi- 
tates the  use  of  another  closed  space,  usually  the  crank  case  on 
the  opposite  side  of  the  piston.  As  regards  the  relative  merits 
of  two  and  four  cycle  engines,  each  has  distinct  advantages  for 
certain  classes  of  work,  as  will  be  made  evident  by  a  careful 
study  of  the  characteristics  of  each  type. 

TH1  TWO-CYCLE  ENGINE. 

A  two-cycle  gasoline  engine  is  one  in  which  an  explosion  takes 
place  in  the  cylinder  every  time  the  shaft  makes  one  revolution. 

Figure  1  represents  in  section  a  single  cylinder  engine  of  the 
ordinary  two-cycle  type.  When  the  engine  is  running  the  fol- 
lowing operations  take  place.  As  the  crank  rotates  in  the 
direction  of  the  arrow  the  piston  (A)  approaches  the  head  of 
the  cylinder  (B)  and  compresses  an  explosive  charge  of  gaso- 
line vapor  and  air.  At  the  extreme  end  of  the  stroke  the 
charge  is  ignited  by  means  of  an  electric  spark  inside  the  cylin- 
der. The  charge  burns  almost  instantly,  as  described  in  the 
first  chapter,  generating  heat,  and  therefore  pressure,  which 
forces  the  piston  away  from  the  cylinder  head  and  delivers 
power  to  the  crank  shaft  (C).  When  the  piston  uncovers  the 
opening  in  the  cylinder  wall  (D),  called  the  exhaust  port,  the 
burnt  gases  escape  to  the  open  air,  usually  being  led  through  a 
sound  muffler  and  piping  to  a  convenient  place  for  discharge; 
but  while  the  piston  is  moving  away  from  the  cylinder  head  a 


FIGURE  1. — Two-port,  two-cycle  engine. 


36         CAKE  AND  OPERATION  OF  GASOLINE  ENGINES. 

mixture  of  vapor  and  air  in  the  crank  case  is  being  slightly 
compressed,  this  compression  being  much  less  than  that  which 
takes  place  within  the  cylinder. 

Just  before  the  piston  reaches  the  crank  end  of  its  stroke  a 
second  opening  in  the  cylinder  wall  (E),  the  inlet  port,  in  the 
opposite  side  of  the  cylinder  from  the  exhaust  port,  is  uncov- 
ered. The  compressed  mixture  in  the  crank  case  expands 
through  the  passage  (F)  and  strikes  the  projection  (K)  on 
the  piston,  which  deflects  the  flow  toward  the  cylinder  head, 
filling  the  cylinder  space  with  a  fresh  charge  of  mixture  and 
expelling  more  of  the  burnt  gases  from  the  exhaust  port.  The 
heavy  flywheel  keeps  the  crank  in  motion  and  starts  the  piston 
again  toward  the  cylinder  head.  When  the  inlet  port  is  cov- 
ered by  the  piston  a  suction  effect  is  created  in  the  crank  case 
by  the  receding  piston,  which  draws  more  gasoline  mixture  from 
the  carburetor  (H).  The  check  valve  (J)  remains  closed  while 
the  gases  in  the  crank  case  are  compressed,  but  opens  readily 
to  admit  new  mixture. 

The  piston  is  now  approaching  the  cylinder  head,  compressing 
the  fresh  charge  of  gas  under  exactly  the  same  conditions 
which  existed  before,  and  this  same  cycle  of  events  continues  to 
take  place  during  every  revolution  of  the  shaft. 

This  type  of  gasoline  engine  is  undoubtedly  the  simplest  ever 
devised.  A  modification,  called  the  three-port,  two-cycle  engine, 
has  proved  to  be  very  successful,  however,  and  these  engines 
are  now  manufactured  in  large  numbers. 

THE  THBEE-POBT,  TWO-CTCLE  ENGINE. 

This  engine  is  very  much  like  the  ordinary  two-cycle  type, 
except  that  a  third  opening  (the  intake  port)  is  provided  in  the 
cylinder  wall,  as  shown  in  figure  2  (G).  This  port,  it  will  be 
noted,  is  always  kept  closed  by  the  piston  except  at  the  time 
when  the  piston  is  near  the  head  end  of  its  stroke.  Hence  the 
crank-case  space  is  tightly  closed  as  the  piston  recedes  and 


FlQORB  2. — Three-ptrt,  two-cyeU  •«jla«. 


37 


38         GAEE  AND  OPERATION  OF  GASOLINE  ENGINES. 

an  increasing  vacuum  is  created  in  the  crank  case,  which 
causes  a  strong  suction  to  draw  in  new  mixture  from  the  car- 
buretor when  the  port  is  uncovered  by  the  piston.  The  check 
valve  (J)  figure  1,  is  eliminated  in  this  style  of  engine,  for  the 
piston,  during  the  crank-case  compression  stroke,  covers  the 
port  leading  to  the  carburetor  and  prevents  escape  of  the  mix- 
ture through  this  passage. 

In  all  other  respects  the  three-port  engine  operates  in  exactly 
the  same  manner  as  the  ordinary  two-port  engine. 

THE   FOUB-CYCLE   GASOLINE   ENGINE. 

As  before  stated,  the  difference  between  the  two-cycle  and 
four-cycle  types  lies  chiefly  in  the  method  of  introducing  the 
explosive  mixture  into  the  cylinder.  We  have  learned  that  in 
the  two-cycle  engine  the  mixture  is  first  drawn  into  a  chamber 
other  than  the  cylinder  space  and  is  forced  therefrom  into  the 
cylinder.  In  the  four-cycle  engine  the  charge  is  first  drawn 
directly  into  the  cylinder  as  the  piston  moves  toward  the  crank 
As  it  is  impossible  to  be  drawing  in  this  fresh  charge  and  at 
the  same  time  have  an  ignited  charge  within  the  cylinder,  twc 
complete  revolutions,  or  four  strokes  of  the  piston,  are  neces- 
sary for  each  power  stroke. 

Figure  3  represents  in  section  a  single  cylinder  four-cycle 
engine.  Suppose  this  engine  is  in  operation,  the  direction  of 
rotation  being  that  shown  by  the  arrow,  the  cylinder  space  con- 
tains a  fresh  charge  of  mixture  and  the  two  valves  ( I )  and  ( E ) 
are  closed.  The  piston  approaching  the  cylinder  head  com- 
presses the  charge.  A  spark  ignites  it  at  the  proper  time  and 
drives  the  piston  toward  the  crank  shaft  just  as  in  a  two-cycle 
engine.  This  motion  of  the  piston  is  called  the  power  stroke. 
When  the  piston  reaches  the  crank  end  of  its  stroke,  the  ex- 
haust valve  (E)  is  opened  by  a  mechanism  driven  by  the  crank 
shaft,  allowing  the  gases  to  escape  from  the  cylinder  as  the 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         39 


FIGURE  3. — Four-cycle  engine. 


40         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

piston  moves  toward  the  cylinder  head,  or  makes  what  is  termed 
the  "  exhaust  stroke." 

The  exhaust  valve  (E)  closes  when  the  piston  has  reached 
the  head  end  of  its  stroke,  and  as  the  piston  again  starts  toward 
the  crank  shaft  the  inlet  valve  (I)  opens,  allowing  fresh  mix- 
ture of  gasoline  vapor  and  air  to  be  drawn  from  the  carburetor 
during  this,  the  intake  stroke  of  the  piston.  The  valve  (I) 
closes  at  the  end  of  the  stroke,  and  both  valves  remain  closed 
as  the  piston  again  moves  toward  the  cylinder  head,  com- 
pressing the  confined  mixture.  This  is  called  the  compression 
stroke,  and  brings  us  again  to  the  same  set  of  conditions  as 
that  with  which  we  started.  The  continuous  operation  of  the 
engine  is  made  possible  only  by  the  tendency  .of  the  heavy  fly- 
wheel, when  set  in  motion,  to  continue  to  revolve,  and  carry 
the  piston  through  the  exhaust,  intake,  and  compression  strokes. 
This  is  true  also,  though  to  a  lesser  degree,  in  the  case  of  the 
two-cycle  engine,  but  it  must  be  remembered  that  throughout 
this  description  of  how  these  engines  work  an  engine  having  but 
one  cylinder  has  been  considered  in  each  instance. 

MULTIPLE-CYLINDER  ENGINES. 

It  is  evident  that  if  two  two-cycle  engines  had  their  shafts 
coupled  together,  two  power  strokes  would  be  obtained  during 
each  revolution  of  the  shafts,  and  if  the  connection  was  so 
made  that  the  cranks  were  opposite  each  other,  one  engine  would 
be  furnishing  a  power  stroke  while  the  other  engine  was  com- 
pressing a  new  charge  of  mixture.  A  much  lighter  flywheel 
would  therefore  be  required  for  a  pair  of  engines  coupled  as 
above  than  would  be  necessary  for  a  single  engine,  the  delivery 
of  power  to  the  shaft  would  be  much  more  uniform,  and  vibra- 
tion would  be  much  less  than  that  of  a  single  engine  of  the  same 
power. 

In  practice,  instead  of  coupling  two  or  more  engines  together 
to  gain  these  advantages,  two  or  more  cylinders  are  so  ar- 


CAKE  AND  OPERATION  OE  GASOLINE  ENGINES.         41 

ranged  that  their  pistons  are  connected  to  one  crank  shaft,  this 
shaft  usually  having  as  many  cranks  as  there  are  cylinders, 
where  the  number  of  cylinders  does  not  exceed  6.  With  8  or  12 
cylinders  there  are  often  but  half  as  many  cranks  as  cylinders, 
pairs  of  cylinders  being  arranged  in  a  V  shape  so  that  their 
pistons  operate  on  one  crank. 

No  matter  how  many  cylinders  an  engine  has,  the  same  series 
of  events  takes  place  in  each  cylinder  as  those  described  in  the 
case  of  single-cylinder  engines,  although  a  single  carburetor  is 
often  used  to  furnish  mixture  to  all  cylinders. 

COOLING  AND  LUBRICATION. 

Every  gasoline  engine,  whether  of  the  two-cycle  or  four- 
cycle type,  must  have  proper  provisions  for  cooling  the  cylin- 
ders and  for  lubrication  of  all  working  parts. 

The  cooling  system  is  required  because,  without  it,  the  rapid 
succession  of  explosions  within  the  cylinders  would  soon  heat 
the  walls  to  such  a  high  temperature  that  lubrication  would  be 
impossible,  and  the  pistons  would  tend  to  stick  in  the  cylinders. 
Even  though  it  were  possible  to  accomplish  lubrication  at  this 
high  temperature,  the  heat  would  soon  become  so  great  that 
the  material  of  which  cylinders  and  pistons  are  made  would  be 
damaged,  and  the  charge  of  mixture  would  be  ignited  before 
the  proper  time,  causing  what  is  termed  "  preignition." 

The  lubricating  (oiling)  system  is  necessary  to  prevent  exces- 
sive friction  and  wear  on  moving  parts  of  the  machine.  In 
some  respects  the  lubricating  system  is  the  most  important  part 
^f  an  engine.  Derangement  of  the  gasoline  or  ignition  systems 
may  cause  great  annoyance  and  make  an  engine  run  badly  or 
refuse  to  run  at  all,  but  such  troubles  seldom  cause  real  damage, 
whereas  failure  of  the  lubricating  system  is  almost  sure  to 
cause  very  serious  damage,  such  as  burned-out  bearings  or 
scored  pistons  and  cylinders. 


CHAPTER  V. 


DESCRIPTION  OF  THE  YARIOUS  PARTS  AND  SYSTEMS 
OF  A  GASOLINE  ENGINE. 

We  have  now  learned  what  operations  must  take  place  when 
a  gasoline  engine  is  running.  The  various  parts  and  systems 
which  are  essential  to  make  possible  these  operations  will  now 
be  described. 

A  complete  practical  gasoline  engine  may  be  considered  as  an 
assembly  of  the  following  parts  and  systems : 

(a)  The  main  engine  body,  made  up  by  cylinders,  crank  case 
or  cylinder  supports,  pistons,  connecting  rods,  crank  shaft,  fly- 
wheels, valves  and  valve-operating  mechanism,  bearings,  and  bed- 
plate. 

(5)  The  gasoline  system,  including  storage  tank,  piping,  car- 
buretor, and  passages  for  conducting  the  mixture  of  air  and 
vapor  to  the  engine. 

(c)  The  ignition  system,  which  includes  the  battery,  dynamo, 
or    magneto,    supplying   the    electric    current,    induction    coils, 
vibrators,  timing  devices,  wiring,  switches,  and  spark  plugs. 

(d)  The   cooling  system,   embracing  water   jackets,   piping, 
pumps,  radiators,  fans,  air  conduits,  etc.,  as  the  case  may  be. 

(e)  The  lubricating  system,  consisting  of  oil  reservoirs,  grease 
cups,  pumps,  regulating  devices,  indicators,  piping,  and  passages. 

Mufflers,  governors,  self-starters,  and  various  other  equipment 
not  absolutely  essential  to  make  the  engine  run  are  quite  neces- 
sary in  some  cases  for  convenience  or  to  adapt  the  engine  to 
certain  uses. 
42 


CARE  AND  OPEEATION  OF  GASOLINE  ENGINES.         43 
THE  MAIN  BODY  OF  THE  ENGINE. 

Cylinders  are  ordinarily  made  of  cast  iron  on  account  of  its 
cheapness,  the  comparative  ease  with  which  this  material  can  be 
cast  into  intricate  shapes  and  machined  to  accurate  dimensions, 
and  the  fact  that  this  material  has  properties  which  make  it 
very  efficient  in  resisting  the  wearing  effect  of  the  reciprocating 
piston.  As  the  cylinders  constitute  the  largest  part  of  an  engine 
their  form  and  arrangement  determines  the  general  arrangement 
of  the  complete  machine.  Most  engines  now  manufactured  have 
vertical  cylinders,  the  head,  or  closed  end,  being  uppermost. 
This  type  occupies  somewhat  less  floor  space  than  is  required 
for  an  engine  of  equal  power  having  horizontal  cylinders.  But 
as  floor  space  in  some  instances  is  not  of  primary  importance 
many  stationary  engines  are  built  with  horizontal  cylinders. 

The  vertical  arrangement  of  cylinders  is  especially  adapted 
for  marine  and  automobile  use,  as  here  only  a  restricted  amount 
of  space  is  available,  and  the  low  position  of  the  crank  shaft 
is  required  to  allow  direct  connection  to  a  propeller  shaft  or 
drive  shaft.  A  few  years  ago,  when  the  automobile  industry 
was  in  its  infancy,  designers  seemed  to  attempt  to  hide  the  pro- 
pelling apparatus  beneath  the  seat  or  body  of  the  vehicle.  En- 
gines having  horizontal  cylinders  were  therefore  used.  Experi- 
ence, however,  showed  the  desirability  of  setting  aside  a"  special 
place  for  the  engine  where  it  would  be  readily  accessible  for 
inspection,  cleaning,  and  repair.  The  location  which  best  ful- 
fills these  conditions  is  at  the  front  of  the  vehicle,  the  engine 
being  set  with  shaft  lengthwise,  and  covered  only  by  a  light 
sheet-metal  hood.  This  arrangement  is  now  universally  used. 

Recently  several  automobile  manufacturers  have  brought  out" 
machines  with  engines  having  8  or  12  cylinders.  If  all  these 
cylinders  were  arranged  vertically  in  a  single  row,  the  complete 
engine  would  be  so  long  that  the  body  of  the  car  would  have 
to  be  very  short,  or  the  length  of  the  car  would  be  too  great 


44         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

for  practical  use  in  street  traffic.  Automobile  engines  having 
8  or  12  cylinders  are  therefore  arranged  with  two  sets  of  4  or  6 
cylinders,  these  two  sets  being  inclined  at  an  angle  of  45°  from 
the  vertical  if  the  number  of  cylinders  is  8,  and  30°  if  there  are 
12  cylinders,  and  so  arranged  that  the  pistons  of  the  forward 
cylinder  of  each  set  are  both  connected  to  the  forward  crank 
of  the  shaft,  the  pistons  of  the  next  two  cylinders  are  connected 
with  the  second  crank,  and  so  on. 

Eight  and  twelve  cylinder  aeroplane  engines  usually  have  the 
cylinders  arranged  in  this  manner,  though  some  makers  place 
the  two  sets  of  cylinders  horizontally.  An  engine  thus  arranged 
is  said  to  have  "  opposed  "  cylinders.  Four  and  six  cylinder 
aeroplane  engines  are  usually  of  the  vertical  type,  this  engine 
being  much  like  that  of  a  four  or  six  cylinder  automobile. 

In  the  design  of  cylinders  a  vast  variety  of  arrangements  of 
minor  parts  has  been  devised.  In  some  cases  the  cylinder  and 
cylinder  head  are  cast  together ;  in  others  the  heads  are  separate 
and  held  in  place  by  bolts.  The  first  arrangement  eliminates  the 
joint  between  the  cylinder  and  head  and  reduces  the  number 
of  separate  parts,  the  second  makes  it  much  easier  to  open  the 
cylinder,  as  by  simply  removing  the  head  the  interior  of  the 
cylinder  and  combustion  space  is  exposed  for  inspection  and 
cleaning. 

Some  two-cycle  engines  have  a  single  casting  for  the  cylinder 
and  crank  case,  removable  plates  being  fitted  to  the  crank  case 
for  access  to  the  working  parts  and  for  installing  the  crank 
shaft.  Other  engines  have  the  cylinders  bolted  to  the  crank 
case.  The  cylinder  of  a  two-cycle  engine  must  be  carefully  de- 
signed and  accurately  made  as  regards  the  location  of  the  ex- 
haust and  inlet  ports,  because  the  economical  operation  of  the 
engine  depends  largely  on  the  time  and  duration  of  inlet  and 
exhaust.  In  a  similar  way  the  design  of  combustion  chamber 
and  valve  arrangement  of  four-cycle  engines  is  of  extreme 
importance  from  the  standpoint  of  economy.  Four-cycle  engines 


CAKE  AND  OPERATION  OF  GASOLINE  ENGINES.         45 

having  inlet  valve  chamber  on  one  side  and  exhaust  valve  cham- 
ber on  the  opposite  side  of  the  combustion  chamber  are  called 
T  head  engines  because  of  the  likness  of  the  shape  of  the 
cylinder  casting  to  the  letter  T.  Where  both  valves  are  on 
one  side  of  the  cylinder  the  engine  is  an  L  head,  the  casting 
having  a  general  shape  like  an  inverted  L.  A  "  valve-in-head  " 
engine  has  its  valves  fitted  directly  in  the  cylinder  head. 

In  multiple-cylinder  engines  each  cylinder  may  be  a  separate 
casting,  or  two  or  more  cylinders  may  be  cast  together ;  that  is, 
11  en  bloc."  This  point  is  determined  by  practical  considerations, 
such  as  the  use  for  which  the  engine  is  built,  the  number  of  a 
single  size  to  be  manufactured,  cost  of  construction,  etc. 

As  to  the  relative  merits  of  these  various  arrangements,  al- 
though manufacturers  of  certain  types  devote  considerable  space 
in  catalogues  and  pamphlets  to  arguments  "proving"  their  de- 
sign is  superior  to  others,  the  fact  remains  that  engines  of  almost 
every  conceivable  design  have  been  successful.  Proper  propor- 
tion of  parts,  high  quality  of  material,  and  good  workmanship 
apparently  have  more  to  do  with  the  ultimate  success  or  failure 
of  an  engine  than  type  and  general  arrangements. 

CRANK  CASE. 

The  ordinary  type  of  two-cycle  engine  must  have  a  separate 
air-tight  crank  case  for  each  cylinder,  because,  as  we  have 
learned,  these  engines  utilize  the  crank  case  as  a  sort  of  pump 
chamber  for  introducing  the  mixture  into  the  cylinder.  With 
engines  working  on  the  four-cycle  principle  there  is  no  abso- 
lute necessity  for  any  crank-case  at  all,  many  engines,  especially 
in  the  larger  sizes,  being  constructed  with  the  cylinders  mounted 
on  columns,  leaving  the  crank  shaft,  connecting  rods,  etc.,  en- 
tirely exposed.  This  arrangement  is  not  practicable  in  small 
engines,  and  the  usual  practice  is  to  inclose  the  crank  shaft 
and  bearings  in  a  case  common  to  all  cylinders,  which  prevents 


6  CARE  AND  OPERATION  OP  GASOLINE  ENGINES. 

dirt  from  reaching  the  working  surfaces  and  facilitates  lubrica- 
tion. The  upper  part  of  this  case  is  usually  made  of  cast  iron 
and  provided  with  webs  to  support  the  crank-shaft  bearings. 
The  lower  part  may  be  of  cast  iron,  pressed  steel,  or  aluminum 
alloy,  and  is  often  arranged  to  form  an  oil  reservoir. 

CRANK  SHAFT. 

Crank  shafts  are  made  of  forged  steel.  In  high-grade  en- 
gines and  those  built  for  service  requiring  a  minimum  weight 
of  engine  per  horsepower  developed,  steel  containing  a  small 
proportion  of  other  elements,  such  as  vanadium  and  nickel, 
which  give  the  metal  greater  strength,  is  used.  Shafts  are 
made  by  forging  the  rough  bar  (or  billet)  into  the  approximate 
shape  required  in  the  finished  shaft,  then  surplus  metal  is  re- 
moved by  machine  tools  and  the  bearing  surfaces  turned  to  ex- 
act dimensions.  For  high-class  engines,  after  being  finished  in 
this  manner,  the  shaft  is  given  a  heat  treatment  to  improve  the 
quality  of  the  metal,  then  all  bearing  surfaces  are  carefully 
ground  to  a  smooth,  glassy  finish. 

The  crank  shaft  revolves  in  the  main  bearings.  In  large  en- 
gines these  bearings  are  carried  by  a  foundation  frame  or  bed- 
plate ;  in  small  four-cycle  engines,  by  webs  of  metal  cast  in  the 
crank  case ;  in  small  two-cycle  engines  by  plates  on  the  sides  of, 
or  between,  the  separate  crank  cases. 

The  position  of  the  cranks  with  relation  to  each  other  in 
multiple-cylinder  engines  is  so  fixed  that  equal  intervals  will 
elapse  between  explosions  in  the  various  cylinders,  insuring  as 
nearly  as  possible  a  constant  delivery  of  power. 

CONNECTING  BODS. 

Connecting  rods  are  usually  made  of  forged  steel,  though  cast 
bronze  is  sometimes  used  in  small  engines.  The  shape  of  cross 


CARE  AND.  OPERATION  OF  GASOLINE  ENGINES.         47 

section  of  the  rod  is  often  made  similar  to  an  I,  H,  or  H-,  as  with 
the  same  weight  of  metal  a  rod  having  one  of  these  shapes  has 
greater  strength  to  resist  bending  than  would  be  obtained  in  a 
plain  round  one.  The  crank  end  of  the  rod  is  enlarged  to  form 
a  bearing  for  connection  to  the  crank  pin.  This  bearing  ordi- 
narily is  in  halves,  one  half  being  on  the  solid  end  of  the  con- 
necting rod,  the  other  half  being  a  cap  held  in  place  by  the 
connecting-rod  bolts.  The  other  end  of  the  rod  is  fitted  with  a 
bearing  to  allow  it  to  swing  on  the  wrist  pin,  or,  in  some  en- 
gines, this  pin  is  fastened  solidly  in  the  connecting  rod  and 
works  in  bearings  in  the  walls  of  the  piston. 

PISTONS. 

Pistons  are  made  of  cast  iron  or,  for  light  high-speed  engines, 
of  aluminum  alloy.  As  it  is  impossible  to  make  a  piston  that 
will  fit  a  cylinder  closely  enough  to  prevent  leakage  and  at  the 
same  time  not  be  so  tight  as  to  cause  excessive  friction  between 
the  surface  of  the  piston  and  the  cylinder  wall,  special  provision 
is  made  to  prevent  leakage  by  turning  recesses  in  the  body  of 
the  piston  and  accurately  fitting  split  metal  rings  of  such  shape 
and  dimensions  that  elasticity  causes  them  to  press  tightly 
against  the  cylinder  wall. 

Two-cycle  engines  are  often  spoken  of  as  being  valveless. 
In  a  certain  sense  this  statement  is  true,  for  no  special  parts 
are  necessary  to  regulate  the  admission  of  mixture  and  the 
discharge  of  burnt  gases  from  the  cylinder,  these  operations 
being  entirely  controlled  by  the  piston  as  it  reciprocates.  To 
properly  regulate  these  events  a  two-cycle  engine  piston  has  a 
projection,  as  shown  in  figure  1  (K),  to  prevent  the  fresh  charge 
passing  directly  across  the  cylinder  and  escaping  through  the 
exhaust  passage.  In  some  three-port  engines  an  opening  is 
provided  in  the  side  of  the  piston  for  the  admission  of  mixture 
from  the,  carbureter  to  the  crank  case. 


48         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

TAT.TTS. 

With  four-cycle  engines,  admission  and  exhaust  valves  before 
referred  to  (fig.  3)  (I  and  E)  are  installed.  These  valves  are 
almost  invariably  operated  by  cams  on  a  shaft  which  is  geared 
to  the  crank  shaft  in  such  a  manner  that  it  makes  one  revolu- 
tion while  the  crank  shaft  makes  two.  On  account  of  this  fact 

cam  shafts  are  sometimes  called  "  half-time  shafts." 

f ,...-, .. 

CAW  SHAFTS. 

The  location  and  arrangement  of  cam  shafts  and  their  driving 
gear  varies  greatly  in  different  makes  of  engines.  With 
T-head,  multiple-cylinder,  four-cycle  engines,  all  cylinders  have 
exhaust  valves  on  one  side  and  inlet  valves  on  the  other  side. 
These  engines  often  have  two  cam  shafts,  one  carrying  the 
cams  that  operate  the  exhaust  valves,  the  other  for  the  inlet- 
valve  cams.  Some  T-head  engines,  however,  have  a  single  cam 
shaft  located  over  the  cylinder  heads,  from  which  all  the 
valves  are  operated  by  levers.  When  two  cam  shafts  are  used, 
and  in  L-head  engines,  which  have  but  one  cam  shaft,  a  loca- 
tion as  shown  in  figure  3  is  usually  chosen,  though  in  some 
ngines  outside  of  the  crank  case. 

In  large  engines  the  cams  are  separate  steel  forgings  fastened 
in  their  proper  places  on  a  plain  shaft;  in  the  smaller  engines 
the  cams  and  shaft  are  usually  one  solid  forging.  While  it  is 
cheaper  to  make  the  cams  and  shaft  separate,  and  assemble  the 
parts  to  form  the  complete  cam  shaft,  there  is  always  danger 
with  a  small  shaft  built  up  in  this  way  that  the  fastenings  will 
work  loose  and  allow  the  cams  to  slip  out  of  position  and  oper- 
ate the  valves  at  other  than  the  proper  time.  In  fact  great 
care  has  to  be  exercised  in  making  cam  shafts,  for  accuracy 
with  which  the  valves  of  a  four-cycle  engine  open  and  close  at 
the  proper  times  Is  absolutely  necessary  for  smooth  running. 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         49 
FLYWHEELS. 

Flywheels  are  made  of  cast  iron  because  this  metal  is  heavy, 
cheap,  and  easily  cast  and  machined.  Aside  from  its  purpose  of 
keeping  the  engine  in  motion  during  intervals  when  power  is  not 
being  delivered  by  the  explosions,  the  flywheel  exercises  a  steady- 
ing effect  on  the  machine  by  its  tendency  to  eliminate  sudden 
changes  in  the  speed  of  rotation  of  the  shaft.  One-cylinder 
stationary  engines  often  have  two  flywheels  of  comparatively 
large  diameter,  for  in  this  case  there  is  no  objection  to  the  con- 
siderable weight,  and  full  advantage  can  be  taken  of  the  steady- 
ing effect.  With  a  two-cylinder  engine,  the  flywheel  may  be 
much  lighter  than  that  required  for  a  single-cylinder  engine  of 
the  same  type  and  power.  This  is  true  to  a  greater  degree  with 
engines  having  more  than  two  cylinders,  until  with  8  or  12 
cylinders  the  necessity  for  a  flywheel  is  almost  eliminated, 
power  being  delivered  by  one  or  more  of  the  several  pistons  at 
all  times.  This  is  one  of  the  advantages  of  multiple-cylinder 
engines,  especially  where  a  light-weight  engine  is  required,  as  in 
<m  aeroplane. 

THE  GASOLINE  SYSTEM. 

The  form  and  construction  of  gasoline  supply  tanks  depend 
almost  wholly  upon  the  class  of  work  the  engine  is  to  perform. 
For  automobiles,  the  tanks  must  have  sufficient  strength  to  resist 
strains  due  to  vibration  and  the  jar  caused  by  rough  roads ;  for 
aeroplanes,  made  as  light  as  possible  without  too  great  a 
sacrifice  of  strength;  and  for  vessels,  usually  so  shaped  that 
they  will  fit  conveniently  the  form  of  the  hull.  Partitions  or 
swash  plates,  dividing  the  tanks  into  several  chambers,  are 
fitted  in  tanks  that  are  not  stationary,  thus  preventing  the 
whole  body  of  liquid  from  shifting  about  suddenly  and  straining 
the  tank.  Small  openings  at  the  top  and  bottom  of  these  parti- 
tions prevent  air  pockets  and  allow  the  liquid  to  flow  slowly 

76616°— 17 4 


50         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

from  one  chamber  to  another.  Stationary  tanks  may  be  of 
almost  any  form  or  size  to  suit  the  local  conditions.  When  the 
engine  is  installed  inside  of  a  building,  it  is  advisable,  if  pos- 
sible, to  locate  the  tank  outside  the  building.  Large  supply  tanks 
are  often  placed  underground,  and  the  gasoline  forced  up 
through  a  pipe  to  the  engine  by  air  pressure,  this  method  of 
feeding  the  gasoline  to  the  engine  being  commonly  used  when- 
ever the  tank  outlet  is  below  the  level  of  the  carbureter.  The 
hole  for  filling  the  tank  should  be  conveniently  located  so  that  a 
common  funnel  of  large  size  may  be  used  when  replenishing  the 
supply. 

Where  the  gravity-feed  system  is  used — that  is,  when  the 
tank  is  higher  than  the  carburetor  and  the  fuel  simply  flows 
through  a  pipe  by  gravity — a  small  hole  in  the  top  of  the  tank 
(usually  in  the  filling  plug)  must  be  provided  to  allow  air  to 
enter  the  tank  as  the  fuel  is  used.  Where  the  tank  is  lower 
than  the  level  of  the  carburetor  the  tank  must  be  air-tight  and 
strong  enough  to  withstand  sufficient  air  pressure  to  force  the 
gasoline  up  to  the  carburetor.  This  pressure  is  maintained  by  a 
small  air  pump  attached  to  the  engine,  by  a  hand  pump,  or  by 
the  pressure  of  the  exhaust  gases.  Recently  some  carburetor 
manufacturers  have  adopted  the  system  of  using  partial  vacuum 
for  drawing  fuel  from  the  tank.  Several  advantages  are  claimed 
for  this  arrangement,  such  as  less  danger  from  leaks  and  elimi- 
nation of  any  possibility  of  the  tank  bursting  from  too  great 
air  pressure. 

The  pipe  for  conducting  gasoline  to  the  carburetor  should  have 
its  suction  end  as  low  in  the  tank  as  possible.  A  stop  cock  or 
valve  should  always  be  fitted  next  to  the  tank,  and  a  suitable 
strainer,  so  arranged  as  to  be  easily  cleaned,  located  next  to 
this  valve  is  a  great  advantage.  The  pipe  line  should  have  as 
few  joints  as  possible  and  must  be  securely  supported  so  that 
there  will  be  no  chance  of  breakage  from  vibration  or  other 
cause. 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         51 

The  mixing  device  or  carburetor  is  located  near  the  cylinder, 
!  of  ten  being  fastened  to  a  support  provided  for  this  purpose  on 
|  the  engine  body.  When  the  industry  was  in  its  infancy  the 
scheme  usually  adopted  to  vaporize  the  gasoline  was  to  pass  air 
over  the  surface  of  a  body  of  the  liquid.  This  involved  at  best 
ti  large  and  cumbersome  device,  sometimes  ingeniously  arranged 
to  secure  a  sufficient  surface  of  liquid  to  make  an  explosive 
mixture.  Although  these  surface  carburetors  worked  fairly 
well  with  high-grade  gasoline,  they  have  been  entirely  sup- 
planted by  a  much  smaller  and  more  efficient  apparatus,  in  which 
the  liquid  is  vaporized  by  being  sprayed  into  a  current  of  air. 
About  the  simplest  device  of  this  sort,  and  one  that  works  well 
for  small  engines  running  at  nearly  constant  speed,  is  shown  in 
figure  4.  It  consists  of  a  sort  of  check  valve  (A)  fitted  with  an 
adjustable  stop  (S)  for  regulating  the  amount  this  valve  may 
open,  and  a  needle  valve  (B)  for  regulating  the  gasoline  feed 
through  a  small  hole  in  the  seat  of  valve  (A).  This  type  of 
carburetor  is  called  a  "  gasoline  generator  valve  "  or  "  vaporizer." 
The  manner  in  which  it  works  is  as  follows :  The  suction  effect 
of  the  engine  is  communicated  to  the  valve  (A)  through  the 
connection  (M)  and  the  chamber  (N),  lifting  the  valve  and 
drawing  in  air  through  the  opening  (O).  As  long  as  the  valve 
(A)  is  closed  no  gasoline  can  flow  through  the  small  hole  (C), 
for  it  is  covered  by  the  valve,  but  the  instant  the  valve  is  lifted 
off  its  seat  a  fine  stream  of  gasoline  sprays  into  the  passage,  be- 
coming vapor  and  mixing  with  the  air  current.  The  purpose 
of  the  needle  valve  (B)  is  to  regulate  the  amount  of  liquid  that 
can  enter,  and  thus  make  the  mixture  richer  or  leaner  as  desired. 
A  coiled  spring  on  the  guide  stem  holds  the  check  valve  snugly 
to  its  seat  when  the  engine  is  not  exerting  the  suction  effect  or 
when  stopped.  This  type  of  carburetor  is  undoubtedly  less 
economical  than  the  more  complicated  forms  hereafter  described, 
but  this  disadvantage  is  quite  offset  in  many  cases  by  its  ex- 


52 


FICURI  4. — Vaporizer. 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         53 

treme  simplicity  and  durability,  especially  when  used  on  sinall- 
powered  two-cycle  engines. 

The  form  of  carburetor  now  used  to  a  greater  extent  than 
any  other,  and  which  seems  destined  to  be  universally  adopted, 
is  that  known  as  the  "  float-feed  "  type.  Figure  5  represents  a 
typical  form  of  float-feed  carburetor  and  illustrates  the  general 
principle  on  which  nearly  all  of  these  carburetors  operate. 
Gasoline  enters  the  bowl  from  the  pipe  line  through  the  needle 
valve  (A).  As  the  depth  of  gasoline  in  the  bowl  increases,  the 
float  (F),  usually  made  of  cork,  rises,  and  through  its  connec- 
tion to  the  needle  valve  (A)  by  the  lever  (L),  shuts  off  the 
flow.  A  level  of  gasoline  in  the  bowl  is  thus  maintained,  which 
is  just  below  the  opening  of  the  spray  nozzle  (N),  but  when 
the  engine  exerts  its  suction  on  the  carburetor  the  liquid  is 
drawn  up  through  this  nozzle  and  sprays  into  the  current  of 
air  flowing  throught  the  passage  (P).  A  needle  valve  (K)  is 
fitted  in  the  spray  nozzle  to  regulate  by  hand  the  size  of  the 
opening,  and  a  gate  or  valve  (X)  is  placed  in  the  discharge 
passage  to  act  as  a  throttle  and  control  the  flow  of  mixture  to 
the  engine.  A  similar  gate  or  valve  (Y)  is  usually  fitted  in  the 
air  intake. 

The  distinguishing  feature  of  this  type  of  carburetor,  and 
the  one  that  makes  it  so  popular,  is  the  automatic  regulation  of 
the  flow  of  gasoline  by  the  float,  since  when  once  properly  ad- 
justed the  apparatus  needs  no  attention,  and  changes  in  the 
depth  of  fuel  in  the  tank  or  in  the  height  of  tank  above  the 
carburetor  cause  no  variation  in  the  rate  of  feed,  this  rate  being 
affected  only  by  the  setting  of  the  throttle  and  the  strength  of 
suction  of  the  engine.  Furthermore,  when  the  engine  is  stopped, 
the  flow  of  gasoline  is  automatically  shut  off.  Of  course,  the 
size  of  the  carburetor  is  determined  by  the  size  of  the  engine 
cylinder,  the  number  of  cylinders,  and  the  rate  at  which  the 
engine  runs,  or,  in  other  words,  by  the  horsepowtr. 


54         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 


Y 


FIGURE  5. — Float-feed  carburetor. 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         55 

In  the  various  makes  of  float-feed  carburetors  can  be  found 
almost  every  conceivable  shape,  arrangement,  and  proportion  of 
parts.  Some  have  two  or  more  spray  nozzles  which  are  ar- 
ranged to  open  successively  as  the  speed  and  power  of  the  engine 
increases  or  as  the  throttle  is  opened.  Others  have  elaborate 
arrangements  for  the  operator  to  admit  heated  or  cooled  air, 
either  before  it  reaches  the  gasoline  spray,  or  in  the  passage 
between  this  point  and  the  engine.  But,  in  general,  it  is  true 
that,  unless  an  engine  is  to  be  operated  by  a  man  so  expert  that 
he  can  take  advantage  of  these  refinements  and  thus  keep  the 
carburetor  adjusted  so  as  to  obtain  the  maximum  economy  of 
fuel,  it  is  much  more  satisfactory  to  have  an  engine  equipped 
with  a  simpler  type  which  is  less  liable  to  disarrangement,  even 
though  some  slight  sacrifice  is  made  from  an  economical  stand- 
point. 

The  passage  for  conducting  the  mixture  from  the  carburetor 
to  the  engine  is  usually  a  plain  piece  of  pipe  when  there  is  but 
one  cylinder.  Where  the  carburetor  furnishes  mixture  for  two 
or  more  cylinders  the  connection  is  usually  a  single  casting  or 
brazed  tubing  with  separate  outlets  to  the  several  cylinders, 
and  is  called  the  intake  manifold. 

IGNITION. 

In  most  gasoline  engines  now  manufactured  ignition,  as  be- 
fore stated,  is  accomplished  by  an  electric  spark.  Two  distinct 
systems  have  been  invented  for  producing  a  spark  within  the 
cylinders  at  the  proper  time  for  igniting  the  charges  of  gas. 

One  system  is  that  known  as  the  "  make-and-break  "  or  low- 
tension  system ;  the  other  is  the  "  jump-spark  "  or  high-tension 
system. 

"  Make-and-break  "  ignition  is  possible  owing  to  the  fact  that 
when  a  metallic  circuit  in  which  a  current  of  electricity  is  flow- 
ing is  broken  a  spark  is  generated  at  the  point  where  the  break 


56         CAKE  AND  OPERATION  OF  GASOLINE  ENGINES. 

occurs.  This  spark  is  caused  by  the  fact  that  air,  vapors,  and 
gases  are  poor  conductors  of  electricity.  Now,  in  breaking  a 
metallic  circuit  the  break  necessarily  begins  with  a  very  slight 
separation  of  the  terminal  points  (no  matter  how  sudden  may  be 
the  break).  The  current  of  electricity,  however  weak,  has  power 
to  leap  across  this  very  slight  break,  and  in  so  doing  heats  the 
intervening  medium  of  air,  vapor,  or  gas  to  such  a  degree  that 
it  glows  and  forms  a  spark  or  "  electric  arc." 

This  spark  is  greatly  increased  in  magnitude  if  a  choke  coil 
(commonly  called  a  "  make-and-break  "  coil)  is  connected  in  the 
circuit.  This  type  of  coil  is  a  very  simple  affair,  consisting  only 
of  an  iron  core  upon  which  is  wound  fairly  coarse  insulated 
wire,  just  as  thread  is  wound  on  a  spool.  In  practice  it  has 
been  found  that  a  battery,  dynamo,  or  low-tension  magneto  fur- 
nishing a  6  or  8  volt  current  will  generate  a  spark  of  sufficient 
intensity  to  fire  a  charge  of  gasoline  vapor  and  air  when  com- 
pressed in  the  engine  cylinder,  provided  a  suitable  coil  is  con- 
nected in  the  circuit  and  the  break  within  the  cylinder  is  suffi- 
ciently sudden. 

The  device  used  to  make  and  break  the  current  within  the 
cylinder  and  thus  generate  a  spark  usually  consists  of  a  sta- 
tionary metal  pin  which  projects  into  the  combustion  chamber 
and  a  movable  latch  with  a  stem  extending  through  the  walls 
of  the  combustion  chamber.  The  stationary  pin  is  kept  from 
metallic  contact  with  the  surrounding  metal  by  an  insulating 
medium  (usually  mica)  to  prevent  the  current  from  flowing 
directly  from  the  pin  to  the  body  of  the  engine.  One  of  the 
terminals  of  the  battery  or  dynamo  is  connected  by  insulated 
wire  to  one  terminal  of  the  coil  and  from  the  other  coil  terminal 
to  this  pin.  The  movable  latch  is  so  located  with  relation  to 
the  stationary  pin  that  when  the  stem  is  slightly  rotated  the 
arm  within  the  cylinder  is  brought  into  contact  with  the  pin. 
The  current  can  then  flow  across  this  point  of  contact  to  the 
latch,  thence  into  the  body  of  the  engine,  and  back  to  the  other 


CAEE  AND  OPERATION  OF  GASOLINE  ENGINES.         57 

terminal  of  the  battery  or  dynamo  through  an  insulated  wire 
connecting  the  body  of  the  engine  to  this  terminal. 

A  mechanical  timing  device  operated  from  the  crank  shaft, 
or  (in  four-cycle  engines)  from  the  half-time  shaft,  is  connected 
to  the  latch  in  such  a  manner  that  the  arm  is  rotated  into  con- 
tact with  the  pin  just  before  the  end  of  the  compression  stroke 
of  the  engine  piston,  thus  establishing  a  current,  and  then  sud- 
denly jerked  away  from  the  insulated  pin,  breaking  the  current 
and  causing  a  spark  at  the  proper  instant  for  ignition  of  the 
compressed  charge.  This  operation  is  repeated  for  each  working 
stroke  of  the  piston. 

For  comparatively  slow-speed  engines,  especially  those  of  the 
two-cycle  type,  the  make-and-break  system  works  very  well  if 
the  operating  mechanism  is  well  designed  and  carefully  made. 

The  advantages  of  this  system  of  ignition  are : 

(a)  Simplicity. — The  electrical  connections  and  the  mechanical 
operating  device  being  so  simple  that  they  are  readily  under- 
stood. 

(b)  Possibility  of  easy  repair. — On  account  of  its  simplicity 
repairs  can  usually  be  made  to  any  part  of  this  system  with  the 
facilities  to  be  found  in  small  repair  shops. 

(c)  Freedom  from  trouble  caused  by  electrical  leakage. — With 
the  low  voltage  required  by  this  system  there  is  seldom  any 
trouble  experienced  due  to  breaking  of  insulation.    This  is  espe- 
cially advantageous  in  marine  work,  where  damp  air  and  water 
often  cause  leakage  from  high-tension  wires. 

The  disadvantages  of  make-and-break  ignition  are : 
(a)  Burning  away  of  contact  points. — The  action  of  the  spark 
burns  the  insulated  pin  and  latch  at  the  point  where  the  break 
occurs,  causing  these  surfaces  to  become  rough  and  dirty  and 
preventing  a  good  contact  to  "  make "  the  current.  To  avoid 
this  trouble  the  pin  and  latch  have  to  be  fitted  with  small  plati- 
num or  platinum-irridum  contact  points,  which  metals  best  resist 


58         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

the  action  of  the  spark.  However,  as  these  metals  are  costly, 
the  expense  of  renewal  is  high. 

(&)  Noise  and  excessive  wear. — The  mechanical  timing  device 
usually  has  reciprocating  parts  that  are  noisy  and  require  fre- 
quent repair. 

(c)  Leakage  of  compression  around  latch  pin. — Loss  of  com- 
pression is  often  caused  by  leakage  around  the  movable  latch 
pin  where  it  passes  through  the  walls  of  the  combustion  chamber. 

JUMP-SPARK  OB  "  HIGH-TENSION  "  IGNITION. 

The  jump-spark  system  of  ignition  depends  upon  the  fact  that, 
if  the  "  electrical  tension  "  or  voltage  is  sufficiently  high,  the  cur- 
rent will  leap  across  a  small  permanent  break  or  gap  between 
the  two  ends  of  the  metallic  circuit  and  cause  a  spark  at  this 
point. 

To  produce  this  high  voltage  either  a  low-tension  current  is 
used  and  a  high-voltage  current  obtained  therefrom  by  means 
of  an  induction  coil,  or  the  high-tension  current  is  produced  di- 
rect by  a  high-tension  magneto,  which  instrument  both  generates 
a  low-tension  current  and  transforms  it  to  high  tension. 

A  jump-spark  ignition  system  using  batteries,  dynamo,  or  low- 
tension  magneto  is  made  up  of  the  following  parts : 

(a)  The  source  of  the  low-tension  current  (battery,  dynamo, 
or  low-tension  magneto)  furnishing  a  current  of  from  six  to 
eight  volts. 

(&)  A  timing  device  or  commutator  for  making  and  breaking 
the  low-tension  circuit  (called  the  primary  circuit). 

(c)  Transforming    induction    coil    with    magnetic    vibrator, 
which,  through  the  action  of  the  primary  current,  generates  a 
high-tension  or  secondary  current. 

(d)  A  distributor  for  directing  the  secondary  current  to  the 
spark  plug  of  the  proper  cylinder  (not  necessary  with  a  single- 
cylinder  engine). 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         59 

(e)  Spark  plugs,  which  are  fitted  in  the  combustion  chambers 
and  furnish  the  gap  across  which  the  high-tension  current  jumps 
and  forms  the  spark. 

(/)  Wiring  and  switches  for  connecting  the  above  apparatus 
in  the  proper  manner.  Wires  for  the  high-tension  circuit  differ 
from  that  which  is  suitable  for  the  low-tension  circuit,  in  that 
the  insulation  has  to  be  much  heavier  to  prevent  the  high- 
electrical  pressure  breaking  the  insulation  and  allowing  the 
current  to  leak  out  into  neighboring  metal  parts  of  the  engine. 

Let  us  consider  how  these  various  parts  are  connected  and 
operate  on,  say,  a  four-cylinder,  four-cycle  engine,  a  battery 
being  used  as  the  source  of  current. 

The  battery  stands  ready  to  cause  a  current  to  flow  around  the 
primary  circuit  whenever  this  circuit  is  "  closed " ;  that  is, 
complete  with  no  breaks  or  gaps.  One  terminal  of  the  battery 
is  connected  to  a  binding  post  on  the  commutator.  This  com- 
mutator is  a  sort  of  switch  so  arranged  on  a  four-cylinder,  four- 
cycle engine  that  it  will  "  make  and  break  "  the  primary  circuit 
four  times  while  the  crank  shaft  makes  two  revolutions,  causing 
a  current  to  flow  for  a  short  interval  at  the  times  when  the 
spark  is  required  for  each  cylinder.  When  the  circuit  is  thus 
closed  by  the  commutator,  current  flows  from  the  battery  through 
the  commutator  contacts  and  through  a  wire  connection  to  the 
proper  binding  post  on  the  induction  coil.  Here  the  current 
flows  around  the  primary  winding  of  the  induction  coil  and 
through  the  vibrator,  magnetizing  the  iron  core  and  causing 
the  vibrator  to  rapidly  interrupt  the  current.  From  the  coil 
the  current  flows  back  to  the  other  battery  terminal.  (In  prac- 
tice it  is  usual  to  have  the  rotating  part  of  the  commutator  in 
metallic  contact  with  the  body  of  the  engine.  The  battery  termi- 
nal first  mentioned  is  then  connected  to  the  body  of  the  engine 
and  is  said  to  "  grounded."  The  current  flows  through  the 
connection,  through  the  body  of  the  engine  and  into  the  sta- 


60         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

tionary  contact  point  or  points  of  the  commutator,  which,  like 
all  other  parts  of  the  circuit,  are  insulated  from  the  engine 
body.) 

Thus  far  we  have  considered  only  the  primary  circuit.  When 
the  circuit  is  closed  by  the  commutator  and  is  being  rapidly  in- 
terrupted by  the  vibrator,  a  high-tension  current  is  "  generated  " 
or  V  induced  "  in  the  secondary  winding  of  the  coil.  The  bind- 
ing post  at  one  end  of  the  winding  is  connected  to  the  central 
connection  of  the  distributor,  this  device  being  a  rotary  switch 
much  like  the  commutator,  but  suitable  for  handling  the  high- 
tension  current,  and  so  arranged  that  it  leads  the  current 
through  four  connections  to  the  spark  plugs.  The  commutator 
in  the  primary  circuit  and  the  distributor  in  the  secondary  cir- 
cuit have  to  be  so  timed  that  contacts  are  made  simultaneously. 

From  the  distributor  the  high-tension  current  flows  to  the 
binding  post  on  the  insulated  spindle  of  the  proper  spark  plug, 
jumps  the  gap  causing  a  spark,  and  returns  through  the  body 
of  the  engine  and  wiring  to  the  other  end  of  the  secondary  wind- 
ing on  the  coil. 

The  distributor  sends  the  high-tension  current  successively  to 
each  spark  plug  at  the  proper  time  for  ignition  in  the  various 
cylinders. 

There  are  several  variations  of  the  above  arrangement,  one  be- 
ing the  use  of  a  separate  coil  and  vibrator  for  each  cylinder. 
This  eliminates  the  use  of  a  distributor,  but  has  a  disadvantage 
in  that  four  vibrators  instead  of  one  have  to  be  kept  in  adjust- 
ment. 

When  an  engine  has  but  one  cylinder  the  commutator  is  ar- 
ranged to  make  and  break  the  circuit  once  each  revolution  of  the 
engine,  if  the  engine  is  two-cycle,  and  once  for  each  two  revolu- 
tions if  four-cycle.  In  this  case  no  distributor  is  necessary,  as 
the  secondary  coil  has  to  send  its  current  to  only  one  spark 
plug. 


CARE  AND  OPEEATION  OE  GASOLINE  ENGINES.         61 

In  any  case  the  commutator  and  distributor  have  to  be  de- 
signed especially  for  the  particular  number  of  cylinders  and  the 
type  of  engine  with  which  it  is  to  be  used. 

As  before  mentioned,  the  high-tension  magneto  is  a  form  of 
electric  generator  which  produces  directly  a  high-tension  cur- 
rent without  the  use  of  a  separate  coil.  Some  of  the  instruments 
of  this  type  are  splendid  examples  of  the  instrument  maker's 
art  and  are  so  arranged  that  they  not  only  produce  the  high- 
tension  current,  but  also  distribute  it  to  the  proper  spark-plug 
connections.  The  magneto  has  to  be  so  driven  from  the  crank 
shaft  or  half-time  shaft  that  its  speed  of  rotation  will  bear  a 
definite  relation  to  the  engine  speed,  determined  usually  by  the 
number  of  cylinders,  and  the  armature  must  be  so  set  or 
"  timed  "  that  sparks  will  be  produced  at  the  proper  instants  for 
igniting  each  charge. 

The  instruments  are  very  complicated,  and  no  person  other 
than  an  expert  should  attempt  to  repair  or  make  other  than 
the  simpler  adjustments  to  the  mechanism.  This  statement  is 
also  true  with  regard  to  induction  coils,  the  only  adjustment 
permissible  in  this  case  being  that  of  the  vibrator. 

It  is  common  practice  to  equip  high-class  engines  with  two 
independent  ignition  systems,  one  employing  batteries  and  in- 
duction coils,  used  only  when  starting  the  engine  and  in  case  of 
emergency,  the  other  being  a  magneto  for  regular  running. 

A  few  engines  are  built  which  use  both  "  make-and-break  " 
and  "  jump-spark  "  ignition. 

Where  two  separate  systems  are  used,  it  is,  in  most  cases, 
for  the  sake  of  reliability,  though  in  engines  required  to  deliver 
a  maximum  of  power  there  is  a  distinct  advantage  in  running 
the  two  systems  in  unison,  as  this  insures  more  instantaneous 
ignition  and  therefore  higher  power. 


62         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 
THE  COOLING  SYSTEM. 

Two  methods  are  used  for  cooling  cylinders  of  gasoline  en- 
gines, one  using  air,  the  other  water  as  the  cooling  agent. 

Probably  the  simpler  system  is  that  which  employs  air,  but 
this  system  is  satisfactory  only  on  engines  having  compara- 
tively small  cylinders.  It  is  used  on  engines  of  motor  cycles, 
on  several  makes  of  aeroplane  engines,  and  in  one  instance 
very  successfully  for  an  automobile  engine. 

In  order  to  furnish  sufficient  surface  from  which  the  heat  can 
pass  (radiate)  to  the  air,  cylinders  of  air-cooled  engines  have 
metal  projections,  either  cast  as  part  of  the  cylinder  body  itself 
or  fitted  as  separate  pieces  around  the  cylinder  casting. 

Moving  air  at  atmospheric  temperatures  cools  a  heated  sur- 
face much  more  rapidly  than  quiet  air.  This  fact  is  used  to 
advantage  in  the  case  of  air-cooled  engines.  On  motorcycles 
air  circulates  rapidly  past  the  cooling  projections  or  fins  on 
account  of  the  motion  of  the. vehicle  itself.  On  an  aeroplane 
both  the  velocity  through  the  air  and  the  blast  from  the  driving 
propeller  accomplishes  this  circulation.  Successful  air  cooling 
of  an  automobile  engine  has  only  been  accomplished  through 
the  use  of  an  ingenious  arrangement  of  air  passages  and  fans. 

For  water  cooling  the  cylinder  has  to  be  surrounded  by  a 
chamber  (water  jacket)  or  passages  through  which  the  water 
is  circulated.  In  most  instances  the  cylinder  castings  are  made 
with  two  walls,  the  outer  one  surrounding  the  combustion  cham- 
ber and  valve  recesses  to  form  the  water  passage.  Where  ex- 
treme lightness  is  essential,  a  thin  metal  case  is  fitted  to  the 
cylinder  casting  with  water-tight  joints  to  form  the  jacket. 

If  an  unlimited  supply  of  water  is  available,  as  is  the  case 
with  marine  engines,  a  water  circulating  pump,  driven  by  the 
engine  itself,  draws  water  from  the  source  of  supply  (in  marine 
practice  from  the  water  in  which  the  vessel  floats)  and  forces 
it  through  piping  to  the  cylinder  jackets.  On  passing  through 


CARE  AND  OPERATION  OP  GASOLINE  ENGINES.         63 

tne  jackets,  the  water  cools  the  cylinders  and  itself  becomes 
heated.  From  the  jackets,  the  heated  water  is  led  by  piping 
to  a  convenient  place  for  discharge  (overboard  in  marine  prac- 
tice). 

For  vehicles,  and  where  the  supply  of  water  is  limited,  a 
radiator  is  used  and  the  heated  water  after  leaving  the  cylin- 
ders passes  through  this  radiator  where  it  is  cooled  and  thus 
made  ready  to  be  pumped  again  through  the  cylinder  jackets. 
The  radiator  used  for  this  purpose  is  made  of  narrow  sheet 
metal  passages  so  arranged  that  air  can  circulate  between  them 
and  reduce  the  temperature  of  the  water.  Tnrough  the  use  of 
a  radiator,  a  comparatively  small  quantity  of  water  is  required, 
this  supply  being  circulated  round  and  round  through  the  cylin- 
ders and  radiator ;  being  alternately  .heated  in  abstracting  heat 
from  the  cylinders,  and  cooled  while  passing  through  the  ra- 
diators. The  cooling  effect  is  increased  by  inducing  a  rapid 
passage  of  air  through  the  radiator.  An  air  fan  is  therefore 
used  in  most  cases  to  accomplish  this  purpose.  Practically  all 
automobile  engines  and  those  of  aeroplanes  using  water  as  the 
cooling  agent  are  cooled  by  this  method. 

Circulation  of  the  water  through  the  jackets  and  radiator  is 
accomplished  in  some  cases  without  the  use  of  a  water  pump. 
This  is  possible  because  water  expands  when  heated,  hence,  if 
the  radiator  is  at  about  the  same  level  as  the  cylinders,  the 
heating  and  cooling  action  of  the  cylinders  and  the  radiator, 
respectively,  will  cause  the  water  to  circulate  through  the  system. 
The  term  "  thermo  syphon  "  is  used  to  designate  this  form  of 
circulation. 

THE  LUBRICATION  SYSTEM. 

Proper  lubrication  (or  oiling)  of  all  parts  that  rub  upon  each 
other  is  an  absolute  necessity  in  all  gasoline  engines.  This 
lubrication  serves  two  purposes ;  it  reduces  the  amount  of  power 


64         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

required  to  move  the  working  parts,  thereby  preserving  thia 
power  for  doing  useful  work,  and  it  reduces  the  amount  of  wear 
on  the  bearing  surfaces. 

Every  properly  designed  engine  has  suitable  arrangements  and 
devices  for  accomplishing  efficient  lubrication  by  distributing 
oil  to  bearing  surfaces  automatically.  The  old-fashioned  method 
of  having  the  operator  go  over  the  engine  with  an  oil  can,  giving 
it  a  squirt  here  and  there  at  more  or  less  irregular  intervals, 
is  entirely  inadequate  for  such  a  machine  as  a  gasoline  engine 
with  its  many  close-fitting  bearings,  high  speed,  and  high  tem- 
peratures. 

Several  methods  are  used  for  automatic  lubrication  of  gasoline 
engines,  the  three  most  common  being  "  splash,"  "  forced  feed," 
and  "  independent  lubricator  feed." 

Splash  lubrication  involves  the  use  of  the  bottom  of  the  crank 
case  as  an  oil  reservoir.  Sufficient  oil  is  supplied  to  this  case 
to  keep  the  level  of  the  surface  at  such  a  height  that  the  lower 
ends  of  the  connecting  rods,  or  projections  on  the  connecting- 
rod  caps,  dip  slightly  and  splash  oil  to  all  parts  of  the  case. 
The  oil  thus  finds  access  to  oil  pockets  and  grooves  that  lead  it 
to  the  bearings.  Indicators  to  show  the  level  of  the  oil  surface 
are  provided,  as  well  as  suitable  means  of  introducing  fresh  oil  to 
the  case  (usually  the  vent  or  "  breather  pipe  "  on  four-cycle  en- 
gines). The  bottom  of  the  crank  case  has  a  drain  plug  for 
removing  old,  worn-out  oil. 

This  method  of  lubrication  is  quite  satisfactory  if  ordinary 
care  is  taken  to  keep  the  oil  at  the  proper  level.  It  supplies  all 
internal  bearings  with  a  copious  supply  of  lubricant  and  has 
the  virtue  of  freedom  from  any  chance  of  mechanical  derange- 
ment. Its  only  bad  features  lie  in  the  fact  that  the  oil  is 
splashed  up  into  the  body  of  the  piston,  where  contact  with 
highly  heated  parts  of  the  engine  tends  to  carbonize  the  oil  and 
lower  its  lubricating  efficiency,  and,  if  the  piston  and  rings  are 
much  worn,  too  much  oil  is  carried  past  these  parts  into  the 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         65 

combustion  chamber,  where  it  forms  excessive  amounts  of 
carbon  deposit. 

All  working  parts  not  located  within  the  crank  case  must 
have  other  provisions  for  lubrication  on  engines  using  the  splash 
system.  These  parts  are  usually  few  in  number  and  such  that 
grease  is  suitable  for  their  lubrication.  This  form  of  lubricant  is 
fed  to  the  bearing  surfaces  by  separate  grease  cups,  often  so 
arranged  that  a  spring  and  plunger  keep  a  constant  pressure  on 
the  grease  and  feed  it  as  required. 

For  forced  feed  lubrication  an  oil  pump  and  system  of  pipes 
and  passages  is  installed  as  a  permanent  part  of  the  engine. 
The  lower  part  of  the  crank  case  is  used  as  an  oil  well,  but  in 
this  system  the  level  is  kept  low  enough  to  prevent  dipping  of 
the  connecting  rods,  the  oil  well  or  "  sump  "  often  being  par- 
tially separated  from  the  crank-case  space  by  a  light  perforated 
metal  plate  or  screen  strainer.  A  pump,  driven  from  some 
rotating  part  of  the  engine,  draws  oil  from  this  well  and  forces 
it  through  a  system  of  pipes  and  holes  leading  to  each  bearing. 
A  supply  of  oil  is  furnished  in  this  manner  to  all  working  parts, 
and,  having  passed  through  the  bearings,  drains  back  to  the 
well,  where  it  cools  and  is  again  available  to  be  pumped  to  the 
bearings.  In  this  manner  the  oil  is  used  over  and  over  again, 
loss  being  made  up  by  occasional  additions  to  the  supply,  intro- 
duced through  the  filling  pipe  (usually  the  "  breather  ").  When 
forced  feed  oiling  is  employed,  extreme  care  must  be  exercised 
to  use  only  clean  oil,  and  keep  it  clean  by  an  efficient  strainer, 
so  placed  that  it  will  collect  all  dirt  before  it  enters  the  distribut- 
ing pipes,  where  it  might  plug  up  the  passages  or  work  into  the 
bearings  and  cut  or  score  them. 

Where  an  independent  lubricator  is  used  for  oil  distribution 
the  crank  case  is  not  necessarily  used  as  an  oil  reservoir,  though 
this  space  is  often  utilized  to  collect  the  waste  oil.  In  the  simpler 
form  the  lubricator  consists  of  a  tank  of  suitable  size  attached 

76610° — 17 5 


66         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

at  some  convenient  place  to  the  upper  part  of  the  engine.  For 
each  bearing  a  needle  valve  and  sight  glass  is  fitted  at  the  tank, 
with  pipes  leading  to  the  separate  bearings,  and  the  oil  flows 
by  gravity  through  these  pipes  at  a  rate  determined  by  the 
amount  the  needle  valves  are  opened.  This  rate  is  regulated 
by  hand  to  the  requirements  of  each  bearing  and  should  be  just 
sufficient  to  properly  lubricate  the  surfaces.  With  this  system 
the  oil  is  used  but  once.  To  avoid  the  necessity  of  hand  regula- 
tion, this  type  of  lubricator  is  sometimes  fitted  with  a  system 
of  mechanical  dippers  operated  by  gearing  or  belt  from  some  ro- 
tating part  of  the  engine  in  such  a  way  that  they  cause  oil  to 
enter  the  pipes  at  a  rate  proportional  to  the  speed  of  the 
engine. 

Independent  force-feed  lubricators  are  much  like  those  described 
above,  except  that  each  oil  pipe  has  a  small  mechanically  oper- 
ated pump  which  causes  the  oil  to  be  delivered  under  pressure. 

Many  engines  are  arranged  to  use  a  combination  of  some  of 
these  three  systems.  With  two-cycle  engines,  lubricating  oil 
is  sometimes  mixed  with  the  gasoline  in  the  supply  tank  and  fed 
through  the  carburetor  to  the  crank  case.  This  is  a  very  con- 
venient way  of  introducing  oil  to  the  engine  and  insures  a  sup- 
ply that  is  proportional  to  the  speed  and  power  developed. 

MUFFLERS. 

Exhaust  gases  leave  the  cylinders  with  such  violence  as  to 
cause  loud  reports  much  like  that  of  a  gun  when  fired.  To  elimi- 
nate this  disagreeable  feature,  the  exhaust  gases  are  led  through 
a  silencing  chamber,  or  muffler.  This  chamber  furnishes  a  space 
in  which  the  velocity  of  the  gases  is  reduced  and  partially 
equalized,  so  that  they  escape  to  the  air  more  as  a  steady  flow 
and  with  practically  no  noise. 

The  ordinary  type  of  muffler  is  cylindrical  and  has  an  interior 
arrangement  of  perforated  baffle  plates  for  changing  the  direc- 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         67 

rion  of  flow  of  the  gases  several  times,  thus  reducing  the  vio- 
lence of  the  separate  exhaust  impulses.  On  marine  engines  it  is 
common  practice  to  use  water- jacketed  mufflers,  the  cooling  effect 
of  the  water  reducing  the  volume  of  the  exhaust  gases,  which 
materially  aids  in  elimination  of  noise. 

At  best,  the  muffler  increases  the  back  pressure  which  the 
exhaust  must  overcome  in  leaving  the  cylinders.  The  work 
necessary  to  rid  the  cylinders  of  burnt  gases  is  therefore  in- 
creased and  the  useful  work  obtainable  from  the  engine  is  less 
than  would  be  the  case  were  no  muffler  fitted.  For  this  reason 
a  muffler  cut-out  which,  when  opened,  allows  the  gases  to  escape 
from  the  exhaust  pipe  direct  to  the  atmosphere  without  passing 
through  the  muffler,  is  often  fitted  on  motor  cars  to  increase  the 
available  power  when  climbing  steep  grades.  However,  in  many 
localities  the  use  of  these  cut-outs  is  prohibited  by  law  on  account 
of  the  noise  which  their  use  involves. 

GOVEBNOBS. 

The  function  of  a  governor  is  to  automatically  control  the 
speed  at  which  the  engine  runs.  For  some  kinds  of  work,  such 
as  driving  an  electric  dynamo,  a  constant,  unvarying  number 
of  revolutions  per  minute  is  necessary  for  satisfactory  service, 
oven  though  sudden  and  large  variations  of  load  occur. 

Gasoline-engine  governors,  like  those  of  most  other  engines, 
usually  depend  upon  centrifugal  force  for  their  operation. 
Weights  and  springs  are  so  arranged  with  a  system  of  links  and 
levers  that,  when  the  mechanism  is  rotated  by  a  positive  driving 
gear  from  some  rotating  part  of  the  engine,  the  weights  change 
position  against  the  tension  of  the  springs,  the  change  of  posi- 
tion becoming  greater  as  the  speed  of  rotation  increases.  This 
movement  is  transmitted  by  suitable  connections  to  the  throttle 
valve  of  the  engine  in  such  a  manner  that  the  throttle  gradu- 
ally closes  as  the  displacement  of  the  governor  weights  in- 
creases. 


68          CAUS  AND  OPERATION  OF  GASOLINE  ENGINES. 

Governors  are  not  often  fitted  to  engines  of  pleasure  vehicles, 
small  motor  boats,  or  aeroplanes,  for  in  each  of  these  eases 
hand  control  of  the  engine  speed  is  sufficient.  They  are  used 
in  the  following  cases  for  the  reasons  given : 

On  engines  used  for  driving  shop  machinery,  dynamos,  etc., 
where  a  constant  speed  is  essential. 

On  medium  and  large  power  marine  engines,  to  limit  the  maxi- 
mum speed  at  which  the  engine  can  run  and  prevent  excessive 
engine  speed  when  the  propeller  leaves  the  water  in  rough  seas 
or  when  the  clutch  is  suddenly  thrown  out. 

And  on  motor  trucks  and  traction  engines  to  limit  the  speed 
at  which  the  vehicle  can  be  driven,  such  regulation  being  neces- 
sary because,  while  the  engine  must  have  sufficient  power  to  haul 
heavy  loads  up  steep  grades,  if  this  power  is  used  to  obtain  high 
speed  on  level  roads,  the  wear  and  tear  on  the  running  gear  be- 
comes excessive.  The  ordinary  driver  can  not  be  trusted  to 
properly  limit  his  speed,  and  automatic  regulation  is  therefore 
resorted  to. 

SELF-STABTEBS. 

One  of  the  worst  features  of  the  gasoline  engine  lies  in  the 
fact  that  it  can  not  be  made  to  start  itself.  Of  course,  if  the 
engine  is  stopped  with  a  compressed  charge  of  gas  in  one  or  more 
of  the  cylinders,  and  there  are  suitable  arrangements  in  the 
igniting  apparatus  for  closing  the  circuit  and  causing  a  spark  in 
this  cylinder,  the  engine  may  start,  provided  the  compression  of 
the  charge  has  not  been  too  much  reduced  by  leakage  past  the 
piston.  This  method  of  starting  is  uncertain  and  can  not  be 
depended  upon.  Until  quite  recently  nearly  all  gasoline  engines 
had  to  be  started  by  hand.  This  in  many  cases  requires  consid- 
erable muscular  effort  and  is  always  more  or  less  dangerous,  to 
say  nothing  of  the  inconvenience  which  it  involves  under  many 
circumstances. 


CAEE  AND  OPERATION  OF  GASOLINE  ENGINES.         69 

The  advantage  of  being  able  to  start  the  engine  of  a  motor 
vehicle  from  the  driver's  seat  is  self-evident,  and  now  that  fairly 
satisfactory  starters  have  been  invented  all  up-to-date  pleasure 
cars  are  so  equipped.  For  stationary  engines,  commercial  vehi- 
cles, and  in  marine  practice  (unless  the  power  is  great)  hand 
starting  is  still  usually  depended  upon  because  of  the  additional 
weight  and  initial  expense  which  self-starters  involve. 

Compressed  air  or  electric  power  is  used  to  operate  these 
starters. 

The  compressed-air  system  is  adapted  for  use  only  on  multiple- 
cylinder  engines.  It  consists  of  a  pump  attached  to  the  engine, 
which  forces  air  into  a  tank,  where  it  is  stored  at  high  pressure. 
Pipes  and  valves  are  so  connected  between  this  tank  and  the 
engine  cylinders  that  the  compressed  air  can  be  admitted  to  the 
proper  cylinders  and  through  pressure  on  the  tops  of  the  pis- 
tons cause  the  crank  shaft  to  turn. 

Electric  self-starters  consist  of  a  storage  battery  for  furnish- 
ing electric  current,  wired  through  a  switch  to  an  electric  motor 
which  is  geared  to  the  shaft.  Some  starters  are  so  designed  that 
the  gears  are  disengaged  as  soon  as  the  engine  starts.  To  start 
the  engine  the  switch  is  closed  and  current  from  the  battery 
runs  the  motor  which  in  turn  runs  the  engine.  As  soon  as  the 
engine  begins  to  run  under  its  own  power  the  disengaging  mecha- 
nism throws  the  starting  motor  out  of  gear  and  breaks  the  elec- 
tric circuit.  The  use  of  this  system  usually  necessitates  the 
attachment  of  an  electric  generator  to  the  engine  for  use  in 
replenishing  the  battery  charge. 


CHAPTER  VI. 


ADVANTAGES    OF    GASOLINE   ENGINES    OVER    OTHER 
FORMS  OF  POWER, 

A  few  pages  will  now  be  devoted  to  discussion  of  the  advan- 
tages which  gasoline  engines  possess  over  other  forms  of  power, 
where  circumstances  are  favorable,  and  what  distinguishing 
features  are  possessed  by  engines  for  various  classes  of  work. 

First  of  all,  it  must  be  understood  that  the  power  of  gaso- 
line engines  is  limited  to  from  one-half  to  300  horsepower. 
This  statement  does  not  mean  that  it  is  impossible  to  build 
engines  for  powers  smaller  or  greater  than  the  limits  given,  but 
that  in  most  cases  the  use  of  very  small  or  large  gasoline  engines 
is  inadvisable. 

Following  are  the  chief  merits  of  gasoline  engines,  where  the 
amount  of  power  required  lies  within  the  above  limits : 

(a)  The  entire  power  plant  can  be  made  to  occupy  compara- 
tively small  space  and  to  depend  in  no  way  upon  outside  appa- 
ratus, wherein  it  differs  from  an  electric  motor,  which  must 
necessarily  be  connected  by  wires  to  the  central  station  or  other 
source  of  current. 

(&)  The  weight  per  horsepower  of  a  gasoline  power  plant  can 
be  made  less  than  that  of  any  other  known  power  producer. 

(c)  Danger  of  destructive  explosions,  such  as  sometimes  occur 
in  steam-power  plants,  is  almost  entirely  eliminated  where  gaso- 
line power  is  used. 
70 


CAEE  AND  OPEBATION  OP  GASOLINE  ENGINES.         71 

(d)  The  average  person  can  learn  in  a  very  short  time  to 
properly  operate  and  take  care  of  these  engines — for  steam 
plants,  in  most  localities,  a  licensed  engineer  must  be  employed. 

(e)  As  now  designed,  gasoline  engines  can  be  kept  clean  and 
made  to  present  at  all  times  a  neat,  tidy  appearance  without 
undue  effort  on  the  part  of  the  attendant,  their  operation  is  not 
accompanied  by  the  disagreeable  tasks  of  handling  dirty  fuel  and 
ashes  as  with  most  steam  plants,  and,  if  properly  adjusted,  no 
smoke  and  very  little  heat  is  produced  as  compared  with  that 
incident  to  the  use  of  steam. 

As  regards  cost  of  operation,  a  general  comparison  between 
gasoline  and  other  forms  of  power  is  difficult  to  make.  Up  to 
about  50  horsepower  the  gasoline  plants  are  invariably  as  eco- 
nomical as  any  other  kind,  excepting  water  power.  Where  more 
than  50  horsepower  is  required  for  a  stationary  outfit,  circum- 
stances may  be  such  that  steam  can  be  used  to  good  advantage. 
The  whole  question  of  cost  of  operation  necessarily  depends,  to 
a  large  extent,  upon  the  cost  of  various  kinds  of  fuel  in  the  local- 
ity where  the  power  is  to  be  used.  For  example,  in  regions 
where  natural  gas  is  abundant,  gas  engines  have  the  advantage, 
or  where  water  power  is  easily  obtained,  electric  current  is 
usually  very  cheap  and  motors  are  largely  used.  At  the  same 
time  cost  of  maintenance  and  wages  of  the  operator  (if  one  has 
to  be  employed)  often  have  more  to  do  with  the  total  cost  of 
operation  than  the  price  of  fuel. 

These  considerations  make  it  extremely  advisable,  whenever 
the  low  cost  of  operation  is  of  primary  importance,  to  submit 
the  question  to  a  mechanical  engineer  for  careful  calculation,  off- 
hand decisions  under  such  circumstances  usually  being  failures. 

However,  for  automobiles,  small  work  vessels,  pleasure  and 
speed  launches,  farm  tractors,  aeroplanes,  small  isolated  electric 
lighting  and  pumping  stations,  for  machinery  on  the  farm  re- 
quiring driving  power,  and  numerous  other  uses,  the  advantages 


72          CARE  AND  OPEEATION  OF  GASOLINE  ENGINES. 

of  gasoline  engines  as  outlined  above  fully  justify  their  adoption 
to  even  a  greater  extent  than  that  which  obtains  at  present. 

To  many  people  the  question  probably  occurs :  "  Why  so  many 
different  types  of  engines ;  why  isn't  one  successful  style  of 
engine  suitable  for  use  under  all  conditions?  " 

Probably  you  have  seen  a  young  athlete  run  a  hundred-yard 
dash  in  10  seconds.  He  appeared  to  be  a  perfect  specimen  of 
the  human  family.  If  this  same  young  man  were  put  to  work  in 
a  ditch,  he  could  probably  shovel  out  about  as  much  earth  as  the 
ordinary  laborer  for  the  first  few  hours,  then  his  hands  would 
begin  to  blister  and  his  back  begin  to  ache,  though  the  laborer 
beside  him  would  be  showing  no  signs  of  distress.  At  the  end 
of  the  day  it  would  probably  be  found  that  the  laborer  had  per- 
formed more  wrork  than  the  athlete ;  in  other  words,  the  laborer 
proved  to  be  the  better  power  plant  as  far  as  ditch  digging  is 
concerned. 

This  is  exactly  the  way  it  is  with  gasoline  engines.  For  high 
speed,  needed  for  comparatively  short  periods,  the  engine  must 
be  built  for  this  particular  kind  of  work,  while  for  heavy,  con- 
stant duty  a  more  rugged  type  of  engine  is  required. 

The  characteristics  of  gasoline  engines  as  designed  for  various 
classes  of  work  will  now  be  briefly  discussed. 

Plenty  of  space  is  usually  available  for  stationary  power 
plants,  and  there  seldom  exists  any  reason  to  limit  the  weight 
of  such  plants.  Hence,  with  the  engines  for  this  class  of  work, 
the  designer  is  free  to  choose  any  arrangement  of  cylinders  and 
other  parts  that  he  may  deem  advisable.  Compactness  in  this 
case  is  of  secondary  importance,  and  the  various  parts  should 
be  so  placed  with  relation  to  each  other  that  all  are  readily 
accessible  for  cleaning,  inspection,  and  repairs.  In  these  en- 
gines the  use  of  expensive  materials  which  possess  great 
strength,  combined  with  little  weight,  may  be  dispensed  with, 
equally  good  results  being  obtained  by  making  the  parts  of 
greater  proportions  from  materials  of  a  cheaper  grade.  The 


CAKE  AND  OPERATION  OF  GASOLINE  ENGINES.          73 

first  cost  of  the  engine  is  thus  reduced,  while  at  the  same  time 
a  very  high  "  factor  of  safety  "  (that  is,  great  strength  of  parts 
for  the  work  they  have  to  do)  can  be  obtained. 

These  remarks  also  apply  to  traction  engines.  In  fact,  weight 
in  the  engine  here  is  a  distinct  advantage,  for  the  pulling  power 
of  such  a  machine  depends  in  a  large  measure  upon  sufficient 
weight  being  placed  on  the  wheels  to  insure  against  slipping. 

In  marine  practice,  where  the  vessel  is  of  heavy  build  and  high 
speed  is  not  required,  the  statements  above  regarding  stationary 
plants  hold  true  for  engines  used  for  propulsion.  In  this  case, 
however,  it  is  essential  that  the  crank  shaft  be  kept  quite  low 
so  that  it  can  be  installed  in  line  with  the  propeller  shaft.  This 
requirement  somewhat  determines  the  general  arrangement  of 
the  plant. 

For  pleasure  launches  and  passenger-carrying  boats  weight 
and  space  occupied  by  the  engine  are  of  more  importance,  while 
in  racing  power  boats  and  very  high-speed  pleasure  craft  every 
possible  measure  is  taken  to  reduce  the  engine  weight  to  the 
minimum.  To  this  end  such  expensive  materials  as  aluminum 
alloy,  vanadium  and  tungsten  steels,  bronze,  etc.,  are  used 
wherever  possible,  but  care  is  taken  to  make  all  parts  of  suffi- 
cient strength  to  guard  against  breakage  and  prevent  the  neces- 
sity for  frequent  overhauling. 

Engines  for  self-propelled  vehicles  have  to  be  fairly  light 
for  the  power  which  they  will  develop  and  must  also  be  very 
compact  so  as  to  occupy  as  little  space  as  possible.  It  is  very 
difficult  to  so  design  an  engine  that  it  will  be  compact  and  also 
have  its  various  parts  accessible.  This  is  a  fault  in  automobile 
engines  that  can  not  be  entirely  overcome. 

It  may  be  well  to  mention  here  the  fact  that  automobile 
engines,  especially  those  for  pleasure  cars,  occupy  a  unique 
position  in  the  gasoline-engine  family.  It  is  only  during  a  very 
small  portion  of  their  whole  existence  that  they  are  called  upon 
to  deliver  their  maximum  power.  Most  of  the  time  they  are 


74          CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

running  at  a  very  small  per  cent  of  their  total  capacity ;  often 
they  simply  idle  while  the  car  is  coasting  down  hill.  These 
conditions  make  possible  the  successful  use  of  smaller  bearing 
surfaces  and  lower  factors  of  safety  than  are  advisable  in 
marine  or  other  engines  which  have  to  deliver  power  constantly 
at  rates  near  their  maximum. 

In  aeroplane  engines  we  reach  the  extreme  as  regards  light 
weight  per  horsepower  developed.  Here  every  possible  measure 
is  taken  to  make  the  engine  light.  Only  the  very  highest-grade 
materials  are  used,  and  the  parts  are  very  carefully  balanced  to 
reduce  vibration  to  the  minimum.  This  necessarily  makes  the 
aeroplane  engine  an  expensive  affair.  The  work  these  engines 
are  required  to  perform  might  be  compared  to  that  of  the  young 
athlete  mentioned  before,  in  running  his  100-yard  dash;  while 
they  do  work,  they  have  to  develop  almost  constantly  all  the 
power  of  which  they  are  capable,  but  this  is  at  the  expense  of 
frequent  lay-ups  for  thorough  overhauling  and  repair. 


CHAPTER  VII. 


INSTRUCTIONS  FOE  RUNNING  GASOLINE  ENGINES. 

Because  of  the  great  variation  of  design  used  by  builders  of 
gasoline  engines  and  the  multitude  of  arrangements  possible  in 
ignition  devices,  lubrication  methods,  cooling  systems,  and  other 
details,  it  is  difficult  to  give  any  but  the  most  general  instruc- 
tions for  running,  which  will  apply  in  all  cases. 

First  of  all,  it  must  be  remembered  that  a  gasoline  engine 
must  be  supplied  with  gasoline  in  order  to  run.  Many  a  thought- 
less person  has  cranked  an  engine,  perspiring,  and  sometimes 
cursing,  when  no  other  fault  existed  than  exhaustion  of  the 
gasoline  supply.  An  engine  certainly  can  not  be  blamed  for  fail- 
ure under  such  circumstances ;  but  this  is  one  simple  illustration 
of  many  conditions  that  can  arise  which  will  make  it  impossible 
for  the  engine  to  do  its  duty  and  against  which  there  is,  and 
always  will  be  but  one  defense — the  display  of  plain  common 
sense  on  the  part  of  the  operator.  With  nearly  all  gasoline 
power-plant  installations  the  procedure  in  starting  up  the  engine 
should  be  as  follows : 

(1)  Turn  on  the  gasoline  supply,  making  sure  that  every  valve 
or  cock  between  tank  and  carburetor  is  open  and  noting  at  the 
time  if  any  leaks  are  apparent.  Do  this  first  of  all,  for  then, 
should  there  be  confined  air  in  the  line  it  can  be  driven  out 
and  the  gasoline  will  find  access  to  the  carburetor  before  you 
are  ready  to  turn  the  engine. 

75 


76         CAEE  AND  OPERATION  OF  GASOLINE  ENGINES. 

(2)  See  that  the  cooling  system,  whatever  the  type,  is  in  or- 
der and  ready  to  do  its  work,  that  fan  belt  is  in  place  and  tight 
enough  to  prevent  slipping,  that  radiator  is  filled  with  water,  or 
that  valves  in  the  circulating  system  are  open,  as  the  case  may 
require. 

(3)  Note  whether  a  sufficient  amount  of  oil  is  in  the  lubri- 
cating system  and  that  this  system  is  ready  to  perform  its  func- 
tion the  instant  the  engine  is  started. 

(4)  See  that  the  needle  valve  of  the  carburetor  is  open  the 
proper  distance  and  that  the  throttle  is  opened  just  enough  to 
allow  the  engine  to   run  at  moderate  speed  with  no  load.    Never 
start  an  engine  with  throttle  wide  open. 

(5)  Now  make  sure  that  gasoline  is  present  in  the  carburetor 
by  opening  the  pet  cock  or  drain  valve  in  the  bottom  to  see  if 
gasoline  drips  out.     (Smell  it.)     As  soon  as  you  are  satisfied, 
close  the  cock. 

(6)  See  that  the  clutch  is  "out"   (if  one  is  fitted)  or  that 
there  will  be  no  load  or  minimum  load  on  the  engine. 

(7)  Throw  the  ignition  switch  into  the  battery  position,  if 
batteries  are  installed ;  if  not,  to  the  dynamo  or  magneto  as  cir- 
cumstances require. 

(8)  See  that  the  spark  control  lever  is  set  for  a  retarded 
(late)  spark.     This  is  most  important,  for  with  the  spark  ad- 
vanced the  engine  is  almost  sure  to  "  kick  back  " — that  is,  start 
in  the  wrong  direction.      If  hand  starting  is  resorted  to,  this 
kick  back  may  seriously  injure  the  operator. 

Always  note  the  position  of  the  spark-control  lever  just  be- 
fore cranking  the  engine. 

(9)  Now  turn  the  engine  by  whatever  means  is  employed;  if 
by  hand,  do  it  in  such  a  way  that  injury  will  not  be  sustained 
should  the  engine,  for  any  reason,  "  kick  back."     With  an  en- 
gine in  proper  adjustment  it  should  start  after  three  or  four 
turns  at  the  most. 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.         77 

(10)  When  the  engine  has  started  and  is  running  regularly, 
advance  the  spark  gradually,  meanwhile  opening  the  throttle 
to  obtain  the  desired  speed. 

In  cold  weather  gasoline  engines  are  often  difficult  to  start. 
Do  not  blame  the  engine  for  this ;  it  is  just  as  natural  as  it  is 
for  a  steam  engine  to  fail  to  start  when  the  water  in  the  boiler 
is  cold.  Gasoline  does  not  vaporize  readily  at  low  temperature, 
hence  an  explosive  mixture  is  difficult  to  obtain. 

Under  such  conditions  a  little  heat  applied  to  the  carburetor 
by  placing  cloths  soaked  with  hot  water  around  it,  or  even  by 
pouring  hot  water  on  the  intake  manifold  and  carburetor,  will 
usually  make  starting  easy.  Another  scheme  is  to  inject  a  little 
warm  gasoline  into  each  cylinder  through  the  priming  cocks,  one 
tea  spoonful  to  each  cylinder. 

TO  STOP  THE  ENGINE. 

(1)  Slow  the  engine  and  throw  off  load  or  reduce  it  to  mini- 
mum. 

(2)  Move  the  spark-control  lever  to  the  position  which  gives  a 
retarded  spark. 

(3)  Throw  the  switch  to  the  "off"  position  (the  engine  now 
stops). 

(4)  Shut  off  lubricator  feeds. 

(5)  Close  such  cocks  or  valves  in  the  gasoline  line  as  may  be 
advisable  to  prevent  possibility  of  leakage. 

Caution. — In  freezing  weather  do  not  fail  to  drain  all  water 
from  radiator,  cooling  jackets,  piping,  and  pumps,  unless  a  non- 
freezing  cooling  mixture  is  used  or  the  engine  is  to  be  started 
again  within  a  short  time.  Otherwise,  the  water  may  freeze  and 
do  serious  damage  because  of  its  tendency  to  expand  and  burst 
the  container. 

When  an  operator  becomes  accustomed  to  running  a  particular 
engine,  he  will  find  many  ways  of  relieving  the  machine  of  undue 


78         CABE  AND  OPERATION  OF  GASOLINE  ENGINES. 

strain.  Sudden  changes  of  load  should  be  avoided,  the  throttle 
should  be  opened  gradually  in  speeding  up,  and  the  engine 
should  never  be  allowed  to  "race";  that  is,  run  at  excessive 
speed  with  no  load.  Any  engine  of  this  kind  will  give  better  and 
more  constant  service  if  it  is  not  forced  to  develop  its  maximum 
power  continually.  For  this  reason  it  is  always  best  to  have  an 
engine  installed  in  the  first  place  that  is  somewhat  more  power- 
ful than  might  be  considered  actually  necessary ;  this  will  prove 
to  be  an  economical  measure.  Likewise,  where  the  engine  is  used 
for  pleasure  service,  as  in  a  launch  or  automobile,  while  an  occa- 
sional "  brush  "  with  a  rival  is  probably  harmless,  a  practice  of 
continually  driving  the  engine  to  its  utmost  will  surely  result,  in 
the  long  run,  in  annoyance  and  trouble  out  of  all  proportion  to 
the  possible  pleasure  derived  from  such  practice.  Be  moderate — 
then  the  engine  will  be  moderate  in  its  demands  for  repairs  and 
Us  cost  of  upkeep. 


CHAPTER  VIII. 


CAKE   AND   MAINTENANCE    OF   GASOLINE    POWER 
PLANT. 

The  problem  of  proper  care  of  an  engine  is  one  "that  should 
receive  more  attention  from  those  who  operate  these  machines 
than  it  usually  does.  It  may  not  be  out  of  place  to  state  here 
that  this  question  of  care  and  maintenance  should  be  studied 
even  before  the  engine  is  purchased,  and  extreme  caution  exer- 
cised to  secure  a  plant  that  is  suitable  in  all  respects  for  render- 
ing the  service  desired.  Many  a  good  gasoline  engine  has  been 
installed  and  proved  a  failure  solely  because  it  was  never  in- 
tended for  the  kind  of  service  to  which  it  was  applied. 

To  guard  against  an  initial  mistake  of  this  kind,  the  person 
about  to  purchase  an  engine  should,  unless  well  informed  on  the 
subject,  seek  the  advice  of  a  competent  gasoline  engine  expert, 
preferably  one  who  is  not  financially  interested  in  any  particular 
make  or  type  of  engine.  By  so  doing  an  outfit  can  be  secured 
that  will  cause  a  minimum  amount  of  trouble  and  render  good 
service  without  undue  attention. 

Assuming  that  the  power  plant  is  adapted  to  its  work,  is 
properly  installed,  and  found  to  render  satisfactory  service,  then 
care  and  maintenance  should  be  such  that  this  happy  state  of 
affairs  may  continue  to  exist. 

Glen nl iness,  proper  lubrication  at  all  times,  and  prompt  repair 
or  adjustment  whenever  the  necessity  for  same  becomes  appar- 

79 


80          CAKE  AND  OPERATION  OF  GASOLINE  ENGINES. 

ent,  prolong  the  life  of  any  engine,  while  the  satisfactory  service 
thus  obtained  repays  an  owner  many  fold  for  the  little  time  and 
attention  required  by  their  accomplishment. 

By  cleanliness,  as  applied  to  a  gasoline  engine,  means  not  only 
a  neat  and  clean  external  appearance,  but  also  strict  care  that: 
foreign  matter  be  kept  from  all  internal  parts.  The  gasoline 
supply  should  always  be  strained  through  chamois  when  it  is 
introduced  into  the  supply  tank.  This  removes  all  water  as  well 
as  dust  and  dirt,  and  eliminates  the  possibility  of  stopping  up  the 
small  passages  through  pipes  and  carburetors.  Likewise,  only 
clean  oil  should  enter  the  lubricating  system,  whether  it  be  of 
the  splash,  -partial  forced  feed,  separate  forced  feed,  or  other 
type,  for  grit  or  dirt  introduced  to  bearing  surfaces  will  surely 
cause  scoring,  and  sooner  or  later  make  adjustment  or  renewal 
necessary.  Whenever  there  is  indication  that  the  interiors  of 
combustion  chambers  are  foul  with  carbon  or  soot  deposit  steps 
should  be  taken  to  remove  same  as  soon  as  circumstances  permit. 

When  any  internal  part  of  the  machine  has  been  opened  for 
inspection  or  repair,  special  care  must  be  exercised  to  see  that 
no  loose  articles,  such  as  bits  of  waste  or  rags,  or  anything  else 
not  belonging  there,  are  left  within  when  the  space  is  again 
closed.  It  is  best  to  use  only  cheesecloth  or  other  woven  fabric 
around  a  gasoline  engine  whenever  work  is  being  done  on  inter- 
nal parts,  for  when  waste  is  used  threads  and  strings  which  are 
bound  to  become  detached  are  liable  to  get  into  and  stop  up  oil 
passages. 

To  accomplish  external  cleanliness,  a  regular  time  for  wiping 
down  the  engine  should  be  fixed  upon.  Circumstances  determine 
how  frequently  such  periodical  cleaning  is  necessary.  When 
the  engine  is  used  intermittently  it  should  always  be  wiped  im- 
mediately after  being  shut  down,  for  the  oil  and  grease  which 
often  finds  its  way  to  external  surfaces  of  the  engine  collects 
dust  and  dirt  even  when  the  engine  is  idle  and  makes  the  clean- 
ing more  tedious  the  longer  it  is  delayed. 


CARE  AND  OPERATION  OF  GASOLINE  ENGINES.          81 

With  reference  to  proper  lubrication,  every  person  operating 
gasoline  engines  should  understand  that  lack  of  lubrication  can 
cause  more  damage  in  10  minutes  than  a  year  of  constant  serv- 
ice under  proper  conditions.  Designers  and  manufacturers  have 
surely  done  all  that  is  possible  to  accomplish  constant  and  suf- 
ficient lubrication  of  their  engines,  but  no  measures  on  their  part 
can  forestall  the  disastrous  results  of  carelessness  or  neglect  on 
the  part  of  the  operator.  If  any  doubt  exists  as  to  the  kind  of  oil 
to  use,  consult  a  competent  person  or  refer  the  matter  to  the 
manufacturers  of  the  engine.  They  will  be  glad  to  furnish  such 
information.  Closely  allied  with  lubrication  is  the  matter  o'f 
cooling  the  cylinders.  If  the  cooling  system  fails,  the  first  indi- 
cation other  than  excessive  heat  will  be  increased  friction  of 
rlie  pistons  in  the  cylinders.  Often  the  pistons  stick  so  tight  that 
the  engine  can  not  be  moved,  and  sometimes  serious  damage  re- 
sults. Where  a  radiator  is  fitted  for  water  cooling,  it  should 
always  be  kept  well  filled  and  invariably  examined  before  the 
engine  is  started,  to  see  that  such  a  condition  exists.  In  boats, 
as  soon  as  the  engine  is  started,  the  operator  should  see  that 
water  is  being  circulated  through  the  jackets,  and  should  the 
least  sign  of  overheating  become  apparent  the  cooling  system 
should  receive  attention  to  find  the  cause,  and  remedy  it. 

After  a  person  has  become  accustomed  to  the  rhythmical 
sounds  made  by  an  engine,  he  should  be  prompt  to  take  notice 
whenever  a  change  takes  place  in  these  sounds  and  try  at  once 
to  find  the  cause.  Lack  of  lubrication  in  any  large  bearing,  over- 
heating of  one  or  more  cylinders,  and  a  multitude  of  other  trou- 
bles will  often  make  their  presence  known  in  this  manner  before 
any  material  damage  is  sustained  and  long  before  actual  per- 
formance of  the  engine  in  delivering  power  will  indicate  their 
presence.  After  a  reasonable  period  of  service  it  is  advisable  to 
give  the  engine  a  thorough  inspection  and  overhauling.  Too 
often  they  are  allowed  to  run  until  wear  or  maladjustment  causes 
76616° — 17 6 


82          CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

breakage  of  some  part,  this  often  doing  serious  damage  to  other 
parts  and  greatly  increasing  the  cost  and  labor  of  placing  the 
engine  in  good  order. 

Overhauling  should  be  carried  out  in  such  a  manner  that,  when 
the  machine  is  assembled,  it  is  to  all  intents  and  purposes  in  as 
good  condition  as  when  it  was  installed.  This  requires  the  sub- 
stitution of  new  parts  for  such  as  are  badly  worn,  renewal  of 
springs  that  have  become  weak,  scraping  of  bearing  surfaces  that 
are  rough,  and  readjustment  of  those  that  are  worn.  Whenever 
a  part  is  found  to  be  cracked,  bent,  or  broken,  a  duplicate  part, 
secured  preferably  from  the  manufacturers  of  the  engine,  should 
be  fitted  rather  than  repairs  being  made  to  the  old  parts.  This 
may  cost  a  little  more  at  the  time,  but  in  the  long  run  will  prove 
to  be  sound  economy. 

To  sum  up  the  question  of  care  and  maintenance  it  is  only 
well  to  repeat:  if  your  power  plant  is  satisfactory  in  the  first 
place,  take  care  to  keep  it  constantly  in  just  as  near  that  same 
condition  as  possible,  let  good  enough  alone,  avoid  makeshift 
temporary  repairs,  and  when  the  least  thing  goes  wrong  re- 
member that  "  a  stitch  in  'time  saves  nine." 


CHAPTER  IX. 


ADJUSTMENTS,  REPAIRS,  AND  OVERHAULING. 

No  person  should  attempt  to  make  even  minor  adjustments 
or  repairs  to  a  gasoline  engine  unless  he  has  a  fair  general  un- 
derstanding of  the  construction  and  mode  of  operation  of  the 
machine.  When  something  goes  wrong,  haphazard  attempts  to 
find  the  trouble  and  remedy  it  are  sure  to  result  in  further  de- 
rangement. These  facts  are  fully  realized  by  manufacturers 
and,  almost  without  exception,  they  furnish  with  each  engine 
complete  printed  descriptions  of  their  products  and  carefully 
prepared  directions  for  properly  adjusting  the  various  parts. 
This  information  should  always  be  carefully  studied  and  thor- 
oughly understood  by  the  person  who  has  charge  of  an  engine. 
He  should  examine  all  parts  of  the  machine  itself,  both  while  it 
is  running  and  when  at  rest.  A  good  way  to  become  acquainted 
with  the  action  of  the  various  parts  is  to  turn  an  engine  slowly 
by  hand  and  see  just  how  they  perform  their  functions.  For 
this  kind  of  study,  the  internal  working  parts  should  be  exposed 
to  view  by  the  removal,  if  possible,  of  cylinder  heads,  valve 
covers,  crank-case  plates,  etc.  The  motion  of  each  part,  the 
relation  of  the  motion  to  that  of  other  parts,  and  the  posi- 
tion of  the  piston  at  the  time  each  operation  takes  place  can 
then  be  observed.  The  whole  mechanism  should  be  studied  in 
this  way  until  the  reason  for  every  action  is  fully  understood. 
Several  hours  can  profitably  be  devoted  to  this  practice.  Then, 
when  trouble  arises,  the  operator  is  better  prepared  to  determine 

83 


84         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 


what  part  is  out  of  order  and  what  is  necessary  to  restore  its 
former  good  condition. 

Of  course  engines  differ  so  radically  in  general  design  and  de- 
tails that  no  definite  directions  can  be  given  for  finding  the 
cause  of  trouble  and  applying  corrections.  However,  a  few  gen- 
eral hints  will  be  offered,  the  following  tabulated  statement 
showing  the  troubles  most  often  encountered,  their  usual  causes, 
and  remedies.  In  each  case,  the  troubles  mentioned  are  to  be 
considered  as  having  developed  while  the  engine  has  been  run- 
ning satisfactorily. 

To  locate  the  seat  of  trouble  in  an  engine  which  fails  to  start 
is  a  far  more  difficult  task  than  finding  what  is  wrong  when  the 
engine  runs  but  does  not  act  properly.  In  the  former  case  a 
systematic  search  must  be  conducted  until  the  fault  is  located. 
Those  parts  of  the  engine  most  likely  to  get  out  of  adjustment 
should  first  be  investigated.  When  a  part  is  apparently  in  good 
order  care  must  be  taken  to  leave  it  in  just  that  condition  in 
which  it  was  found,  lest  other  trouble  than  that  which  first  ex- 
isted be  created. 


CAHE  AND  OPERATION  OF  GASOLINE  ENGINES. 


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88         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 


CAEE  AND  OPERATION  OF  GASOLINE  ENGINES.         89 

After  a  little  experience  with  gasoline  engines  some  people 
seem  to  have  very  little  difficulty  in  quickly  finding  the  cause 
of  trouble ;  others  seem  never  to  acquire  this  knack.  The  reason 
for  this  lies  in  the  ability  of  some  minds  to  grasp  the  relationship 
between  causes  and  effects.  Extraordinary  mental  develop- 
ment or  unusual  intelligence  on  the  part  of  the  operator  is  not 
essential,  but  it  can  safely  be  said  that  the  person  who  uses  his 
head  and  reasoning  powers  when  running  a  gasoline  engine  will 
find  less  necessity  for  using  his  hands  than  the  person  who  de- 
pends solely  on  printed  directions  and  his  mechanical  skill  in 
repairing  broken  machinery. 

When  mechanical  troubles  develop,  repairs  should  only  bo 
made  by  someone  who  knows  how  to  perform  such  work.  Read- 
ing matter,  explaining  how  valves  should  be  ground,  bearings 
fitted  and  adjusted,  cam  shafts  timed,  and  similar  repairs  ac- 
complished, will  aid  a  person  in  learning  how  to  do  this  work, 
but  in  addition  to  this  it  is  absolutely  essential  that  a  person 
should  see  such  work  actually  done  by  a  competent  mechanic  be- 
fore he  attempts  to  do  it  himself.  If  no  damage  could  result 
from  failure  to  make  such  repairs  in  a  proper  manner,  then  the 
case  would  be  different,  but  unfortunately,  poor  workmanship 
often  causes  damage,  and  many  a  good  engine  has  practically 
been  destroyed  by  attempts  of  a  novice  to  accomplish  repairs 
that  would  test  the  skill  of  a  trained  machinist. 

A  general  overhauling  should  only  be  necessary  after  the 
machine  has  been  in  service  for  a  considerable  length  of  time. 
If  possible,  it  should  be  done  where  the  facilities  of  a  well- 
equipped  machine  shop  or  garage  are  available,  for  very  often 
special  tools  or  the  use  of  machine  tools  such  as  a  lathe,  shaper, 
or  drill  press  will  be  required.  A  thorough  overhauling  should 
involve  the  dismantling  of  the  whole  machine  and  putting  each 
part  in  good  condition;  then,  in  reassembling,  the  parts  are 
carefully  adjusted  with  relation  to  each  other,  bearings  are  set 
so  that  the  effect  of  former  wear  is  eliminated,  parts  worn 


90         CARE  AND  OPERATION  OF  GASOLINE  ENGINES. 

badly  are  renewed ;  in  fact,  all  possible  steps  taken  to  restore 
the  machine  to  a  condition  approximating  that  which  existed 
when  it  was  new. 

While,  as  before  stated,  it  is  most  difficult  to  explain  just  how 
t  repairs  should  be  accomplished,  a  few  cautions  as  to  certain 
things  that  should  never  be  attempted  by  the  average  operator 
will  not  be  amiss. 

Never  take  apart  a  magneto,  except  to  remove  the  cover  and 
adjust  contact  points.  Neither  the  magnets  nor  the  armature 
should  ever  be  removed  from  the  body  of  the  instrument  except 
by  an  expert.  When  the  machine  fails  to  work  take  it  or  send 
it  to  a  service  station  or  to  a  competent  repair  man.  These 
remarks  also  apply  to  induction  coils.  Adjustment  of  vibrators 
is  easily  accomplished  and  often  necessary,  but  no  attempt 
should  ever  be  made  to  examine  the  interior  or  repair  it.  This 
again  is  work  for  a  skilled  man. 

Never  change  the  shape  or  size  of  needle  valves,  floats,  or 
other  parts  of  a  carburetor.  They  were  carefully  designed  by 
men  who  understood  the  principles  of  carburetion.  Proper  ad- 
justment by  means  of  the  facilities  provided  is  all  that  is  neces- 
sary to  make  a  carbureter  do  its  duty.  If  not,  send  it  back  to  the 
maker. 

Alterations  of  the  engine  or  any  part  of  it  with  the  view  to 
improvement  should  never  be  attempted  unless  you  are  abso- 
lutely sure  that  it  will  be  for  the  best.  Such  attempts  are  usu- 
ally failures,  often  cause  serious  damage,  and  are  likely  to  be 
expensive. 


CHAPTER  X. 


CONCLUSION. 

In  concluding  this  pamphlet  it  is  only  fair  to  the  gasoline 
engine  to  state  that  it  is  now  a  well-perfected  invention.  Its 
development  has  been  remarkably  rapid  during  the  twenty-odd 
years  that  it  has  been  in  practical  use.  To  be  sure,  in  its 
early  days  this  type  of  power  fell  into  ill  repute  when  a 
bucking  or  entirely  inert  launch  engine  or  gasoline  automobile 
was  the  target  for  ridicule  from  bystanders  and  an  inex- 
haustible source  of  ideas  for  the  cartoonist.  But  this  period 
of  disgrace  was  largely  due  to  overenthusiasm  on  the  part  of 
the  manufacturers  themselves,  who  advertised  their  engines 
with  such  expressions  as  "  Simple  as  A  B  C's,"  "Any  child 
can  run  it,"  and  so  on,  which  statements,  while  they  may  have 
sold  a  few  engines  to  the  unsuspecting  public,  only  caused  re- 
sentment on  the  part  of  owners  when  they  discovered  that  a 
gasoline  engine,  like  any  other  mechanism,  required  at  least  a 
small  degree  of  mechanical  ability  on  the  part  of  the  operator 
and  would  stand  but  a  limited  amount  of  abuse.  In  spite  of  all 
this  the  merits  and  possibilities  of  gasoline  power  for  small 
units  was  so  apparent  that  engines  of  this  type  continued  to 
be  installed  and  used  in  spite  of  their  defects.  In  the  mean- 
time manufacturers,  through  improvement  of  design,  use  of 
better  materials,  and  superior  workmanship,  constantly  im- 
proved and  continue  to  improve  their  products. 

91 


92         C ABE  AND  OPEHATjCON  OE  GASOLINE  ENGINES. 

Present-day,  engines.  are  far  frpm  "fool  proof,"  though  many 
have  been  so  perfected  that  a  person  with  no  mechanical 
knowledge  can  run  them  successfully  for  limited  periods,  and 
the  actual  care  can  be  left  to  others.  Thousands  of  automo- 
biles are  now  run  in  this  manner,  the  driver  knowing  nothing 
whatever  of  the  care  and  operation  of  the  engine  further  than 
how  to  start  and  stop  it,  while  garage  mechanics  look  after  its 
adjustment,  lubrication,  cleanliness,  and  general  condition. 

It  is  to  be  expected  that  this  idea  will  be  carried  still  fur- 
ther, and  that  the  gasoline  engine  of  the  future  will  be  one 
which  produces  practically  no  noise  or  vibration,  which  has  ab- 
solutely no  working  part  exposed,  except  the  shaft  where  power 
is  delivered,  and  which  has  its  parts  so  nicely  designed  and  pro- 
portioned that  no  one  part  will  show  excessive  wear  while 
other  working  parts  are  apparently  as  good  as  new.  Such  an 
engine,  if  properly  supplied  with  fuel,  water,  and  lubricants, 
would  continue  to  give  service  throughout  its  natural  life,  the 
same  as  a  horse  or  mule  if  properly  fed,  until  finally  a  general 
breakdown  like  that  of  the  "  one-hoss  shay  "  ends  its  career 
and  sends  it  to  the  scrap  heap. 


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